CTLA4 and lung cancer: IC inhibitors targeting programmed cell death receptor 1 (PD-1) and its ligand (PD-L1), cytotoxic T lymphocyte-associated protein 4 (CTLA-4), and lymphocyte activation gene-3 (LAG-3) are over-expressed in several cancers, such as lung cancer [3], melanoma [4], and triple-negative breast cancer (TNBC) [5].