Recently, great progress has been made in identifying novel diagnostic and prognostic biomarkers for lung cancer, including RBR E3 ubiquitin ligase [32], prostaglandin E synthase 3 (PTGES3) [33], fibroblast activation protein (FAP) [34], checkpoint inhibitor immunotherapy targeting programmed cell death 1 (PD1), and programmed death ligand 1 (PDL1) pathways [35,36]. This evidence concerns the gene PDCD1 and lung cancer.