The battle against cancer continues to evolve, with oncolytic viruses emerging as a groundbreaking and promising avenue for innovative treatment. This paper provides a comprehensive overview of oncolytic viruses, a unique class engineered to selectively infect and destroy cancer cells, eliciting an immune response against tumors. Beginning with a historical perspective, the narrative explores the mechanisms of action, types of oncolytic viruses, and notable clinical successes, including the FDA approval of a melanoma therapy.