CTLA4 and neoplasm: These molecules regulate T-cell proliferation and differentiation to enhance antitumor immunity and serve as key mediators of tumor immune evasion.[2] Since the approval of ipilimumab, the first anti-CTLA-4 monoclonal antibody, in 2011,[3] an increasing number of ICIs have been clinically approved, revolutionizing cancer treatment and significantly improving patient outcomes.