CTLA4 and cancer: Since the introduction of the first ICI, ipilimumab (human IgG1 k anti-CTLA-4 monoclonal antibody) in 2011, six additional ICIs have been approved for cancer therapy by regulatory agencies (6), becoming a mainstay in the treatment of several neoplasms, including non-small cell lung cancer (NSCLC) and malignant melanoma.