PDCD1 and non-small cell lung carcinoma: Paucity in the development of traditional chemotherapeutic drugs and resistance of some forms of cancers to available therapies has spurred the emergence of immunotherapy targeting programmed cell death protein 1 (PD-1), programmed cell death 1 ligand 1 (PDL-1), and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) for the treatment of NSCLC [5].