Importantly, in the last decade, the scientific breakthrough of immunotherapy against immune checkpoint inhibitor (ICI)–programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1) and recent progress in the understanding of cancer immune response have led to the approval of immunotherapy for early and advanced NSCLC stages [14,20,21,22,23]. The gene discussed is PDCD1; the disease is cancer.