CTLA4 and breast cancer: Since 2011, various immune checkpoint (ICB) inhibitors such as PD1 and CTLA-4 monoclonal antibody and adaptive immune cell therapy such as CAR-T, CAR-NK, and Lymphokine-Activated Killer cells (LAK) have achieved a good clinical therapeutic effect in the treatment of malignant tumors like melanoma, lung cancer, gastric cancer, and breast cancer.