PDCD1 and neoplasm: Immune checkpoint inhibitors (ICIs), particularly antibodies to programmed cell death protein 1 (anti-PD1) and programmed death ligand 1 (anti-PD-L1), are used in NSCLC with the rationale that blocking programmed cell death protein 1 (PD-1) on activated T cells and programmed death-ligand 1 (PD-L1) on tumor cells could reinvigorate cytotoxic TCD8+ cells by activating host adaptive immunity [8,9].