With the discovery of immune checkpoints (i.e., cytotoxic T lymphocyte antigen-4 (CTLA-4), V-domain immunoglobulin suppressor of T cell activation (VISTA), program cell-death 1 (PD-1), program cell-death ligand 1 (PD-L1) and T-cell immunoglobulin and mucin domain 3 (TIM-3)) (Deng et al., 2024; Mok et al., 2024; Zuo et al., 2024; Jin et al., 2024), immunotherapy, exemplified by immune checkpoint blockade (ICB), has revolutionized the treatment of cancer (Zhu et al., 2021). This evidence concerns the gene PDCD1 and cancer.