Immunotherapy harnesses the body’s own immune system to recognize and destroy cancer cells. It has transformed treatment for several cancers, particularly melanoma, lung cancer and some blood cancers.

A central approach uses immune checkpoint inhibitors, such as antibodies targeting CTLA-4, PD-1 or PD-L1. Tumors exploit these checkpoints to dampen immune responses; blocking them releases the brakes on T cells, enabling stronger antitumor activity. Clinical studies show durable responses in a subset of patients, including long term remission, but not all patients benefit and some develop serious autoimmune-like side effects.

Adoptive cell therapies take immune cells from a patient, modify or expand them, then reinfuse them. CAR T cell therapy engineers T cells with synthetic receptors that recognize specific tumor antigens. These therapies have produced striking remissions in certain leukemias and lymphomas. Challenges include toxicity such as cytokine release syndrome, limited success in solid tumors and high cost and complexity.

Cancer vaccines aim to stimulate immunity against tumor antigens. They can be made from peptides, proteins, DNA or RNA, or from whole cells. Personalized vaccines targeting neoantigens derived from an individual’s tumor mutations show promise in early trials by expanding tumor specific T cells, especially when combined with checkpoint inhibitors.

Research now focuses on rational combinations of immunotherapies with each other and with chemotherapy, radiotherapy or targeted drugs to overcome resistance. Scientists are also developing biomarkers to predict who will respond, exploring the tumor microenvironment, and designing safer, more precise cell therapies. Immunotherapy has become a key pillar of oncology, with ongoing efforts to broaden its effectiveness and reduce toxicity.