Currently, one hotspot of cancer immunotherapy is the ICB therapy that inhibits programmed cell death protein 1/programmed cell death ligand 1 (PD-1/PD-L1) and cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) signaling to reinvigorate CD8+ T cells in the tumor microenvironment (TME) to potentiate killing of tumor cells (12). The gene discussed is PDCD1; the disease is cancer.