PDCD1 and non-small cell lung carcinoma: Immune checkpoint inhibitors (ICIs), which disrupt inhibitory pathways such as cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), programmed cell death-1 (PD-1) protein, and its ligand PD-L1 to potentiate antitumor immunity, have become a cornerstone of treatment for advanced non-small cell lung cancer(NSCLC), substantially improving 5-year survival rates (3, 4).