CTLA4 and non-small cell lung carcinoma: Significant progress has been achieved in the first- and second-line immunotherapy of advanced NSCLC in recent years, particularly immune-checkpoint inhibitors, (ICIs)including programmed death-1 (PD-1) inhibitors, programmed death-ligand 1 (PD-L1) inhibitors, and cytotoxic T lymphocyte associated antigen-4 (CTLA-4) inhibitors [6, 7].