CTLA4 and lung cancer: To date, since the immune checkpoint inhibitors (ICIs) targeting programmed cell death-1/ligand-1 (PD-1/PD-L1) and cytotoxic T lymphocyte antigen-4 (CTLA-4) have led to a paradigm shift in lung cancers [45, 46], the efficacy of ICIs on older patients remains controversial as old persons inclusion is lacking in current clinical trials [47].