Cancer immunotherapy has transformed oncology by harnessing the immune system to specifically target cancer cells, offering reduced systemic toxicity compared to traditional therapies. This review highlights key strategies, including adoptive cell transfer (ACT), immune checkpoint inhibitors, oncolytic viral (OV) therapy, monoclonal antibodies (mAbs), and mRNA-based vaccines. ACT reinfuses enhanced immune cells like tumor-infiltrating lymphocytes (TILs) to combat refractory cancers, while checkpoint inhibitors (eg, PD-1 and CTLA-4 blockers) restore T-cell activity. OV therapy uses engineered viruses (eg, T-VEC) to selectively lyse cancer cells, and advanced mAbs improve targeting precision. mRNA vaccines introduce tumor-specific antigens to trigger robust immune responses. Despite significant progress, challenges like immune-related side effects, high costs, and immunosuppressive tumor microenvironments persist. This review underscores the need for combination strategies and precision medicine to overcome these barriers and maximize the potential of immunotherapy in personalized cancer treatment.