Tumor-infiltrating lymphocyte (TIL) therapy is a new cellular immunotherapy approved by the FDA in 2024 for the treatment of advanced melanoma, particularly in patients who have failed prior immunotherapy.[1] Clinical studies show that this therapy achieves a 36% response rate in patients with metastatic melanoma, and up to 20% of patients show a complete response.[1] Patients have seen long-term responses lasting more than two years.[1] TIL therapy works by using the patient's own immune cells to fight cancer through a single injection of T-cell therapy.[1] All available studies on TIL therapy are as effective or more successful than the control drugs used.[1] Adverse effects are mostly associated with chemotherapy caused by lymphodepletion required before TIL therapy itself.[1] TIL therapy represents a breakthrough treatment option for patients with advanced melanoma who no longer respond to traditional immunotherapies.