CTLA4 and lung cancer: Some immunotherapies, such as programmed death-1 (PD-1) and programmed death ligand-1 (PD-L1) inhibitors or cytotoxic T lymphocyte-associated antigen 4 (CTLA4) therapies, have shown an optimistic antitumor effect in melanoma [3, 4], lung cancer [5], gastrointestinal cancer [6] and ovarian cancer [7].