The introduction of immunotherapy, especially immune checkpoint inhibitors (ICIs), which boost the antitumor activity of T cells and rescue immune surveillance by blocking programmed cell death protein 1 (PD-1), programmed cell death 1 ligand 1 (PD-L1), and cytotoxic T lymphocyte associated antigen 4 (CTLA-4), has elicited tremendous excitement owing to its success in various types of cancers, including melanoma (1), hepatocellular carcinoma (2), and lung cancer (3). This evidence concerns the gene PDCD1 and lung cancer.