Immunotherapy has emerged as a game-changing approach in oncology, offering targeted strategies to activate the immune system against cancer. Checkpoint inhibitors, such as anti-PD-1 and anti-CTLA-4 drugs, have led to significant progress in treating aggressive tumors like melanoma and certain lung cancers. CAR-T cell therapy, an innovative method involving the genetic reprogramming of a patient’s T cells, has shown remarkable success, particularly in hematologic cancers. Moreover, therapeutic cancer vaccines are gaining traction as a means to prime the immune system against tumor-specific antigens. These therapies provide hope for long-term remission and even cures in some cases. Research and case studies continue to refine their application, addressing challenges like resistance, side effects, and cost-effectiveness.