CTLA4 and lung cancer: ICIs such as anti-programmed death-1 (PD-1)/programmed death ligand-1 (PD-L1) antibodies and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) are widely administered to patients with different kinds of neoplasms such as lung cancer, melanoma, renal cancer, urothelial cancer, and Hodgkin’s lymphoma (5–7).