Immunotherapy: Understanding the Basics

Learn more about this innovative cancer treatment.

a middle-aged Black woman patient consults with her male Middle-Eastern doctor

Updated on October 14, 2022

Immunotherapy is a type of treatment that harnesses the power of your own immune system to fight disease. As a treatment for cancer, it has dramatically changed oncology care, and has shown particular effectiveness for certain difficult-to-treat cancers.

The treatment tends to be more tolerable than chemotherapy and radiation, and it may extend the lives of patients for months or even years.

What is immunotherapy?

The treatment works in two main ways, either by boosting the immune system so it can better fight cancer or by making the immune system smarter so that it can find and attack cancer cells.

There are several types of immunotherapy that can be used to treat cancer. They include the following:

  • T-cell transfer therapy: With this treatment (also known as adoptive cell therapy), immune cells called T-cells are taken from the patient’s blood. They are then modified in a lab to make them better-equipped to attach to and kill tumor cells, then injected back into the patient. Specific forms include chimeric antigen receptor (CAR) T-cell therapy and tumor-infiltrating lymphocytes (TILs) therapy.
  • Checkpoint inhibitors: These are drugs that alter aspects of the immune system called checkpoints that ordinarily help prevent immune responses from being too strong (which can harm healthy cells). Once the drugs block checkpoints, the immune system may have a stronger response to cancer cells.
  • Monoclonal antibodies: These are immune system proteins developed in a lab to attach to certain parts of a tumor cell to help the immune system better identify and respond to cancer cells.
  • Immunomodulators: These are drugs that boost various aspects of the immune system to help it target certain cancers.
  • Vaccines: Unlike conventional vaccines that help prevent disease, when used in cancer therapy, these enhance the body’s immune response to cancer cells.
  • Oncolytic viruses: This form of treatment uses viruses that are often specially modified in a lab to infect tumor cells, causing them to self-destruct. Once the tumor cells have been targeted by the virus, the immune system can then continue working to eliminate the tumor.

Immunotherapy may be administered in a number of different ways, including through a vein (intravenously), orally with pills, topically with creams, or by being directed to a specific body part (such as in the case of bladder cancer).

Unlike the one-size-fits-all, blunt-force approach of chemotherapy and radiation, immunotherapy treatments tend to hone in on cancer in novel ways that are more individualized to both the condition and the patient.

What types of cancer can immunotherapy treat?

Immunotherapy has been successful as an approach to treating a variety of cancers, including those of the lungs and uterus. Other cancers that may be addressed with immunotherapy include:

Lymphoma: CAR T-cell treatment is used as a second-line therapy for patients with some non-Hodgkin lymphomas that haven’t responded to other treatments. The therapy shrinks tumors in many patients.  

Bladder cancer: Checkpoint inhibitors such as PD-1 and PD-L1 inhibitors help the immune system attack cancer cells to shrink or slow their growth. These are given intravenously and can be used for people with bladder cancer when tumors regrow after chemotherapy or who have invasive cancer that is removed with surgery but have a high risk of regrowth afterward.

Esophageal cancer: PD-1 inhibitors can be used to treat esophageal cancers that can’t be removed surgically or that return after other treatments. This immunotherapy increases survival rates for patients with these persistent cancers.  

Kidney cancer: Patients who have had kidney cancer removed by surgery but are at a higher risk of recurrence may benefit from immunotherapy, such as PD-1 and PD-L1 inhibitors.

Prostate cancer: Vaccines can be used to activate the body’s immune response and fight advanced prostate tumor cells. The therapy can extend patients’ lives.  

Advantages and drawbacks

Most immunotherapy treatments are tolerated better than are traditional treatments. Chemotherapy and radiation kill not only cancer cells but can also harm healthy cells, leading to side effects such as loss of appetite, increased bleeding and bruising, severe nausea, vomiting, diarrhea, fatigue, and hair loss.

Some immunotherapy patients experience no side effects. But because this treatment does alter the immune system, it may cause the immune system to attack healthy cells during and after treatment, potentially leading to serious side effects.

These may include:

  • Rashes
  • Nausea and vomiting
  • Muscle and joint pain
  • Fever
  • Headaches
  • Cough or problems breathing

Some other less common—though potentially dangerous—side effects include kidney failure, problems with fertility, and issues with the endocrine and immune systems. For example, certain checkpoint inhibitors impair the thyroid gland or cause it to become overactive and may similarly hamper the functioning of the adrenal gland. In rare cases, checkpoint inhibitors may also cause a form of diabetes to develop.

Immunotherapy is a constantly changing treatment that has been shown to save lives and expand opportunities for treating cancer. This therapy has enabled healthcare providers to treat a range of complicated, aggressive cancers and help people live longer, cancer-free.

Article sources open article sources

American Cancer Society. How Immunotherapy Is Used to Treat Cancer. Page last updated on September 27, 2019.
Cancer Research Institute. What is Immunotherapy? Updated October 2020.
Cancer Research Institute. Immunotherapy Timeline of Progress. Page accessed September 2, 2022.
Cancer Research Institute. Benefits of Cancer Immunotherapy. Page accessed October 14, 2022.
Eno J. Immunotherapy Through the Years. Journal of the Advanced Practitioner of Oncology. 2017;8(7):747-753.
National Cancer Institute. Immunotherapy to Treat Cancer. Page last updated on September 24, 2019.
Lymphoma Research Foundation. CAR T-cell therapy. Page accessed on September 2, 2022.
National Health Service. Side Effects: Chemotherapy. Page last reviewed January 29, 2020. Side Effects of Immunotherapy. May 2022.
Devon Carter. CAR T cell therapy side effects in lymphoma patients. MD Anderson Cancer Center. September 23, 2019.
National Cancer Institute. Immune Checkpoint Inhibitors. Reviewed: April 7, 2022.
American Cancer Society. Immunotherapy for Bladder Cancer. Last Revised: September 20, 2021.
American Cancer Society. Immunotherapy for Kidney Cancer. Last Revised: November 22, 2021. Side Effects of Radiation Therapy. July 2022.
Waldman AD, Fritz JM, Lenardo MJ. A guide to cancer immunotherapy: from T cell basic science to clinical practice. Nat Rev Immunol. 2020;20(11):651-668.

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