The ORRs of PD-L1 or PD-1 monoclonal antibody treatment are in the 12%–19% range (10, 12, 13), while CTLA-4 blockade appears minimally active (14) Therefore, advances in immune treatment strategies that can further boost the anti-BC immune response by altering the immune-suppressive TME are needed. Here, CTLA4 is linked to breast cancer.