As the “predecessors” in immune checkpoint inhibitors, the development of anti-CTLA-4 monoclonal antibodies in recent years has not been ideal. From the perspective of approved indications, their single-drug treatment uses are few and can only be paired with PD-1/L1 inhibitors. If we look at the failure cases of clinical research, it will be even more heart-wrenching.   So the question is, what is blocking the anti-CTLA-4 monoclonal antibody? The research…