Immunotherapy is a revolutionary cancer treatment that leverages the body’s own immune system to fight cancer. It works by stimulating or restoring immune cells to recognise and destroy cancer cells. This therapy is particularly effective for melanoma, lung cancer, kidney cancer, and certain blood cancers. Immunotherapy can be used alone or in combination with chemotherapy, radiation, or targeted therapy. Checkpoint inhibitors, CAR-T therapy, and cancer vaccines are some of the advanced approaches in this field. Unlike traditional treatments, immunotherapy can produce long-lasting effects by training the immune system to prevent cancer recurrence. Patients may experience fewer side effects than conventional chemotherapy, though immune-related reactions are monitored carefully. Personalised immunotherapy is guided by biomarker testing and tumour profiling. The treatment emphasises precision medicine and individualised care. Ongoing research continues to expand its use to more cancer types. Immunotherapy represents a paradigm shift in oncology, offering hope where other treatments may have failed.