Impaired tumor-specific effector T cells contribute to tumor progression and unfavorable clinical outcomes.As a compensatory T cell-dependent cancer immunoediting strategy,adoptive T cell therapy (ACT) has achieved encouraging therapeutic results,and this strategy is now on the center stage of cancer treatment and research.ACT involves the ex vivo stimulation and expansion of tumor-infiltrating lymphocytes (TILs) with inherent rumor reactivity or T cells that have been genetically modified to express the cognate chimeric antigen receptor or T cell receptor (CAR/TCR),followed by the passive transfer of these cells into a lymphodepleted host.Primed T cells must provide highly efficient and long-lasting immune defense against transformed cells during ACT.Anin-depth understanding of the basic mechanisms of these living drugs can help us improve upon current strategies and design better next-generation T cell-based immunotherapies.From this perspective,we provide an overview of current developments in different ACT strategies,with a focus on frontier clinical trials that offer a proof of principle.Meanwhile,insights into the determinants of ACT are discussed,which will lead to more rational,potent and widespread applications in the future.