ICIs targeting programmed cell death protein 1 (PD-1), programmed death-ligand 1 (PD-L1), or cytotoxic T lymphocyte–associated antigen 4 (CTLA-4) have demonstrated remarkable treatment efficacy in cancers like melanoma and non–small cell lung cancer (NSCLC) (1). The gene discussed is PDCD1; the disease is non-small cell lung carcinoma.