CTLA4 and non-small cell lung carcinoma: In addition to driver-mutation targeted therapies, the discovery and utilization of immune checkpoint (ICP) inhibitors in NSCLC has provided new and hopeful treatment options for many patients (27).The ICP describes an immunomodulatory process that downregulates T-cell effector responses and is mediated in part by the B7 ligand binding to the cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) receptor and the programmed cell death ligands 1 and 2 (PD-L1 and PD-L2) binding to the programmed cell death protein 1 (PD-1) (28).