Advances in Adoptive Cell Therapies in Cancer: From Mechanistic Breakthroughs to Clinical Frontiers and Overcoming Barriers.

Adoptive cell therapies (ACTs) have revolutionized cancer treatment by harnessing the specificity and potency of T lymphocytes. Chimeric antigen receptor (CAR)-T cells have achieved landmark successes in B-cell malignancies and multiple myeloma. Tumor-infiltrating lymphocytes (TILs) and T-cell receptor (TCR)-engineered T cells offer complementary strategies to target solid tumors and intracellular antigens. Despite these advances, ACTs face challenges including cytokine release syndrome, neurotoxicity, on-target/off-tumor effects, manufacturing scalability, and immunosuppressive tumor microenvironments. Innovative strategies, such as dual-antigen targeting, localized delivery, checkpoint blockade combinations, gene-editing, and machine-learning-guided antigen discovery, are being used to mitigate toxicity, enhance efficacy, and streamline production. As CAR-T, TIL, and TCR modalities converge with advances in manufacturing and computational biology, the next generation of "living drugs" promises broader applicability across hematologic and solid tumors, improved safety profiles, and better treatment outcomes for patients. This review details the evolution of ACTs from first-generation CAR constructs to next-generation "armored" designs. It also focuses on the development and clinical deployment of TIL and TCR therapies. Furthermore, it synthesizes mechanisms, pivotal clinical trial outcomes, and ongoing challenges of ACTs. It also highlights strategies that will drive broader, safer, and more durable applications of these therapies across hematologic and solid tumors.