Recently, immunotherapy has become a hot topic since the approval of programmed death-1 (PD-1)/programmed death-1 ligand 1 (PD-L1), cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) ICIs by the U.S. Food and Drug Administration (FDA)with satisfying efficacy in advanced cancers (9, 10). However, low response rate, emergence of drug resistance, and tolerability concerns appeared quickly. This evidence concerns the gene CTLA4 and cancer.