Types of Immunotherapy for Cancer

What Is Cancer Immunotherapy?

Immunotherapy is a form of biological treatment that helps the immune system identify, attack, or control cancer. Some treatments remove signals that prevent immune cells from working. Others mark tumor cells for destruction, deliver immune-stimulating substances, or collect and modify a patient’s immune cells before returning them to the body.

Unlike traditional chemotherapy, which generally attacks rapidly dividing cells, immunotherapy usually works by changing the relationship between the cancer and the immune system. That does not automatically make it gentler. An activated immune system can become overenthusiastic and attack healthy tissues, rather like a security guard who starts questioning everyone in the building, including the employees.

Immunotherapy may be used alone or combined with chemotherapy, radiation, surgery, or targeted therapy. The best approach depends on the cancer type, stage, previous treatments, overall health, tumor biomarkers, and the specific immunotherapy being considered.

1. Immune Checkpoint Inhibitors

How checkpoint inhibitors work

Immune checkpoint inhibitors are among the most widely used types of immunotherapy for cancer. The immune system normally uses checkpoint proteins to prevent T cells from damaging healthy tissue. Unfortunately, some cancers exploit these checkpoints to switch off the very T cells that might otherwise attack them.

Checkpoint inhibitors block that “stop” signal. By releasing the immune system’s natural brakes, these medicines allow T cells to recognize and attack cancer more effectively. Important checkpoint targets include PD-1, PD-L1, CTLA-4, and LAG-3.

Examples and cancer types

Examples include pembrolizumab, nivolumab, cemiplimab, atezolizumab, durvalumab, avelumab, ipilimumab, and the nivolumab-relatlimab combination. Depending on the drug and tumor characteristics, checkpoint inhibitors may be used for melanoma, lung cancer, kidney cancer, bladder cancer, head and neck cancer, liver cancer, colorectal cancer, stomach cancer, cervical cancer, lymphoma, and several other malignancies.

Some checkpoint inhibitors have tumor-agnostic indications. This means treatment may be selected because the tumor has a particular molecular feature, such as mismatch repair deficiency or high microsatellite instability, rather than because it began in a specific organ.

Possible side effects

Common effects may include fatigue, rash, itching, diarrhea, reduced appetite, cough, nausea, and joint discomfort. More serious immune-related reactions can involve the colon, lungs, liver, thyroid, adrenal glands, pituitary gland, kidneys, heart, nervous system, or other organs. These problems may appear during treatment or after treatment has ended, so new symptoms should never be saved for the next appointment like an unimportant grocery-list item.

2. T-Cell Transfer Therapy

T-cell transfer therapy, also called adoptive cell therapy, involves collecting immune cells, preparing or modifying them in a laboratory, multiplying them, and returning them to the patient. The goal is to provide an army of T cells that is better equipped to recognize cancer.

CAR T-cell therapy

Chimeric antigen receptor T-cell therapy begins with T cells collected from a patient’s blood. In a laboratory, the cells are genetically modified to produce a receptor that recognizes a particular antigen on cancer cells. The engineered cells are multiplied and infused back into the patient after a short course of lymphodepleting chemotherapy.

CAR T-cell therapy has been especially important for certain blood cancers, including some leukemias, lymphomas, and multiple myeloma. It has been more difficult to use against solid tumors because solid cancers may lack a uniform target, restrict immune-cell entry, or create a hostile tumor microenvironment. Researchers are testing multi-target CARs, armored CAR T cells, and other designs intended to overcome those barriers.

Major risks include cytokine release syndrome, which may cause fever, low blood pressure, breathing problems, and rapid heartbeat. Neurologic toxicity may cause confusion, tremors, difficulty speaking, seizures, or reduced alertness. Blood-count suppression and infections are additional concerns. Because these reactions can become serious quickly, treatment is provided by teams trained to recognize and manage them.

Tumor-infiltrating lymphocyte therapy

Tumor-infiltrating lymphocytes, or TILs, are immune cells that have already entered a tumor. Their presence suggests that they recognize something suspicious, but there may be too few of them or the tumor environment may have weakened their activity.

With TIL therapy, a tumor sample is surgically removed, promising lymphocytes are isolated, and billions of copies are grown in a laboratory. The patient receives lymphodepleting treatment, followed by an infusion of the expanded cells and additional immune stimulation.

In February 2024, the U.S. Food and Drug Administration granted accelerated approval to lifileucel for certain adults with unresectable or metastatic melanoma that had progressed after specified previous treatments. It became the first FDA-approved cellular therapy derived from a patient’s tumor for this setting.

Engineered T-cell receptor therapy

T-cell receptor, or TCR, therapy also modifies a patient’s T cells, but it allows the cells to recognize tumor-related proteins presented from inside cancer cells. Unlike CAR T cells, which generally recognize targets on cell surfaces, TCR therapies can potentially address a wider range of tumor antigens.

This treatment requires a suitable cancer antigen and compatible human leukocyte antigen type. In 2024, the FDA granted accelerated approval to afamitresgene autoleucel for certain previously treated adults with advanced synovial sarcoma whose tumors and HLA type meet specific criteria.

3. Monoclonal Antibodies and Bispecific Antibodies

Monoclonal antibodies

Monoclonal antibodies are laboratory-made proteins designed to recognize a specific target. Not every monoclonal antibody is classified as immunotherapy; some work mainly as targeted treatments. However, many help the immune system by attaching to cancer cells and marking them for destruction.

Rituximab, for example, binds to the CD20 protein on B cells and is used in several B-cell blood cancers. Other antibodies may block cancer-growth signals, carry a drug or radioactive substance to tumor cells, or activate immune mechanisms that damage the targeted cell.

Bispecific antibodies

A bispecific antibody can recognize two different targets at once. Many are designed to grab a cancer cell with one end and a T cell with the other, bringing attacker and target into extremely close proximity. Think of it as arranging the world’s least comfortable blind date for the tumor cell.

Bispecific treatments are used for certain leukemias, lymphomas, and multiple myeloma, while many additional products are being studied for solid tumors. Depending on the medicine, risks may include cytokine release syndrome, infections, low blood counts, neurologic reactions, liver abnormalities, or infusion-related symptoms.

4. Cancer Treatment Vaccines

Preventive vaccines, such as vaccines against human papillomavirus or hepatitis B, reduce the risk of cancers linked to particular infections. Cancer treatment vaccines have a different job: They are given after cancer develops and are intended to train the immune system to recognize tumor-related antigens.

Sipuleucel-T is an individualized cellular vaccine used for certain patients with advanced prostate cancer. A patient’s immune cells are collected, exposed to a prostate cancer-related protein in a laboratory, and then returned through an infusion.

Researchers are also studying personalized vaccines based on neoantigens, which are abnormal proteins created by mutations unique to a patient’s tumor. Some experimental vaccines use messenger RNA technology, while others use peptides, proteins, tumor cells, or specialized immune cells. These vaccines may eventually work best in combination with checkpoint inhibitors that prevent tumors from switching off the vaccine-stimulated response.

5. Oncolytic Virus Therapy

Oncolytic viruses are modified viruses designed to infect and destroy cancer cells while stimulating an immune response against the tumor. As infected cancer cells rupture, they release tumor antigens and inflammatory signals that may attract immune cells to the area.

Talimogene laherparepvec, commonly called T-VEC, is an oncolytic virus therapy used for certain melanoma tumors that can be injected directly. It is based on a modified herpes simplex virus. Researchers are studying other viruses for brain tumors, bladder cancer, pancreatic cancer, and additional solid tumors, frequently in combination with checkpoint inhibitors.

Side effects may include fever, chills, fatigue, nausea, and soreness at the injection site. Because these treatments use live or modified viruses, patients may receive detailed instructions about covering injection sites and limiting accidental exposure to household members.

6. Immune System Modulators

Immune system modulators stimulate broad immune activity rather than aiming at one precise tumor target. They include cytokines, immune-stimulating medicines, and treatments such as bacillus Calmette-Guérin.

Cytokines

Cytokines are signaling proteins that help immune cells communicate. Interleukin-2 can activate and expand T cells and natural killer cells, while interferon alfa can slow tumor growth and increase immune activity. These treatments played a larger role before checkpoint inhibitors became widely available, but they may still be used in selected situations.

Because cytokines can activate the immune system throughout the body, side effects may include fever, chills, fatigue, nausea, diarrhea, confusion, low blood pressure, low blood counts, infections, and organ complications. High-dose cytokine treatment may require intensive monitoring.

BCG for bladder cancer

Bacillus Calmette-Guérin, or BCG, contains weakened bacteria related to the organism used in a tuberculosis vaccine. When placed directly into the bladder through a catheter, it triggers a local immune response that can attack bladder cancer cells. BCG has long been an important treatment for certain forms of non-muscle-invasive bladder cancer.

Patients may experience urinary urgency, burning, blood in the urine, fever, or flu-like symptoms. Persistent high fever, severe weakness, breathing difficulty, or worsening illness requires urgent medical evaluation because serious infection, although uncommon, can occur.

How Doctors Choose an Immunotherapy

There is no single “best” immunotherapy for all cancers. Oncologists may consider the tumor’s location, stage, growth pattern, molecular profile, immune environment, and previous treatment response. A therapy that works beautifully for one cancer may accomplish very little in another that looks similar under a microscope.

Biomarkers that may guide treatment

• PD-L1 expression: Higher expression may support the use of certain checkpoint inhibitors, although it is not a perfect predictor.
• Mismatch repair deficiency or microsatellite instability: Tumors with these features may contain many abnormalities that make them easier for the immune system to recognize.
• Tumor mutational burden: A high number of mutations may increase the likelihood that immune cells will detect abnormal proteins.
• Cell-surface antigens: CAR T cells, bispecific antibodies, and monoclonal antibodies require recognizable targets such as CD19, CD20, or BCMA.
• HLA type and tumor antigen expression: These factors are important for some engineered TCR therapies.

Biomarker testing narrows the possibilities, but it cannot guarantee a response. Some patients with favorable markers do not benefit, while others with less promising test results may respond. Cancer biology has a habit of treating neat rules as optional suggestions.

What the Immunotherapy Experience Can Be Like

The following section describes common practical experiences reported across cancer care. It is not the story of one specific patient, and individual treatment plans can differ substantially.

Before treatment begins

The first surprise is often the amount of preparation. Patients may expect an infusion and instead receive a small encyclopedia of appointments: blood tests, imaging, heart or lung testing, biomarker analysis, medication reviews, and conversations about autoimmune conditions, organ transplants, infections, pregnancy, fertility, and previous treatments.

People preparing for cell therapy may have additional steps. T cells must be collected, transported, engineered or expanded, tested, and returned to the treatment center. During this manufacturing period, the care team may recommend another therapy to keep the cancer controlled. Patients may also need to arrange transportation, temporary housing near the hospital, caregiver support, and time away from work.

Infusion days may feel surprisingly ordinary

For many checkpoint inhibitors or antibody treatments, an infusion visit can resemble other outpatient cancer appointments. A nurse checks vital signs, reviews symptoms, draws blood, and starts an intravenous line. The medicine may run for less than an hour or considerably longer, depending on the product and whether premedications are needed.

Some patients read, work on a laptop, watch television, or become deeply invested in choosing the least disappointing snack from the infusion-center basket. The quietness of the appointment can feel strange when the treatment itself carries such emotional weight.

Side effects do not always follow a predictable schedule

One person may experience fatigue and a mild rash. Another may feel almost completely normal. A third may develop inflammation in the thyroid, colon, lungs, liver, or another organ. Symptoms can arise after the first dose, after several months, or occasionally after treatment has stopped.

That unpredictability makes communication essential. Cancer teams frequently ask patients to report diarrhea, worsening cough, shortness of breath, chest pain, severe headache, confusion, vision changes, yellowing skin, unusual weakness, reduced urination, fever, or a rapidly spreading rash. Early treatment of immune-related reactions may prevent a mild problem from becoming a hospital-sized problem.

Patients sometimes hesitate to report symptoms because they fear the oncologist will stop a treatment that may be working. In reality, prompt reporting gives the care team more options. Treatment may be paused, tests may be ordered, or corticosteroids and other immune-suppressing medicines may be prescribed. Managing toxicity is part of immunotherapy, not evidence that the patient has somehow failed it.

Cell therapy can be more intensive

CAR T-cell, TIL, and engineered TCR therapies often involve hospitalization or close monitoring. The period after infusion can be physically and emotionally demanding. Fever may trigger immediate evaluation for infection or cytokine release syndrome. Nurses may repeatedly ask patients to write a sentence, name objects, or answer simple questions to detect early neurologic changes.

Recovery does not necessarily end at discharge. Blood counts may remain low, infection precautions may continue, and driving or operating machinery may be restricted for a period specified by the treatment team. Caregivers often become record keepers, medication managers, chauffeurs, and professional worriersall before breakfast.

Waiting for scans is its own challenge

Immunotherapy does not always shrink tumors immediately. In uncommon cases, immune cells entering a tumor can temporarily make an abnormal area appear larger on imaging. Doctors may therefore consider symptoms, scan patterns, laboratory results, and follow-up imaging before deciding whether treatment is working.

Patients often describe the days before a scan as emotionally draining. A practical routine can help: write down questions, bring an updated medication list, record new symptoms, and ask the oncologist exactly how response will be measured. Clear information does not remove uncertainty, but it gives uncertainty fewer places to hide.

Everyday strategies that may make treatment easier

Many patients find it useful to keep a daily symptom log that includes bowel movements, temperature, breathing changes, energy level, appetite, skin changes, pain, and sleep. Bringing the log to appointments can reveal patterns that are difficult to remember afterward.

It is also wise to carry the cancer center’s emergency contact information and an immunotherapy treatment card when one is provided. Emergency clinicians need to know that symptoms could be immune-related, especially if the patient is treated far from the oncology center.

Finally, patients may benefit from asking for help early. Oncology dietitians, social workers, physical therapists, financial counselors, mental health professionals, and palliative care specialists can address problems that medication alone cannot fix. Palliative care is not limited to the end of life; it can be used alongside active treatment to improve comfort, function, and quality of life.

Questions to Ask the Oncology Team

• Which type of immunotherapy is being recommended, and what is its treatment goal?
• Does my tumor have a biomarker that makes a response more likely?
• Will immunotherapy be used alone or with chemotherapy, radiation, surgery, or targeted therapy?
• Which side effects require an immediate call or emergency care?
• Could my medications or autoimmune condition affect treatment safety?
• How and when will the medical team determine whether treatment is working?
• Are there clinical trials that may be appropriate for my cancer?

The Bottom Line

The major types of immunotherapy for cancer include immune checkpoint inhibitors, CAR T-cell therapy, TIL therapy, engineered TCR therapy, monoclonal and bispecific antibodies, cancer treatment vaccines, oncolytic viruses, cytokines, and immune system modulators such as BCG.

These treatments do not all work in the same way. Some remove immune brakes, some mark cancer cells, some recruit T cells, and others deliver billions of laboratory-prepared immune cells. Their benefits and risks depend on the specific cancer, treatment target, patient health, and medical setting.

Immunotherapy has changed the outlook for some cancers, but it is not a universal cure or a guaranteed replacement for established treatments. The most useful question is not simply, “Can immunotherapy treat cancer?” It is, “Does this particular immunotherapy make biological and clinical sense for this particular patient?” That answer belongs in a detailed conversation with an experienced oncology team.