PDCD1 and non-small cell lung carcinoma: Numerous clinical trials have confirmed that monoclonal antibodies targeting programmed cell death protein 1/programmed death ligand 1 (PD-1/PD-L1) and cytotoxic T lymphocyte-associated protein 4 (CTLA-4) can improve overall survival in patients with advanced non-small cell lung cancer (NSCLC) (4).