HAVCR2 and neoplasm: T cell–based immunotherapies include ICIs [PD-1/PD-L1, CTLA-4, lymphocyte activation gene 3 (LAG-3), T-cell immunoglobulin and mucin domain-3 (TIM-3), T-cell immunoreceptor with immunoglobulin, and ITIM domain (TIGIT)], ACTs [CAR-T, tumor-infiltrating lymphocyte (TIL), and cytokine-induced killer (CIK)], and Tregs-targeted therapy strategy.