CTLA4 and cancer: The over expression of co-inhibitory molecules of the immune system (e.g., CTLA4, PD-1) in tumor infiltrating lymphocytes (TILs), which leads to the suppression of T cell activity against cancer cells, has led to several studies investigating the immune checkpoint inhibitors (ICIs) as a potential agent in cessation of disease progression in multiple cancers, including NSCLC [91,92,93].