Currently, the US Food and Drug Administration (FDA) approves three categories of ICIs for the treatment of NSCLC, including cytotoxic T lymphocyte antigen 4 (CTLA-4) inhibitors, programmed death 1 receptor (PD-1) inhibitors, and programmed cell death receptor ligand 1 (PD-L1) inhibitors. The gene discussed is CTLA4; the disease is non-small cell lung carcinoma.