Notably, the combination of E7046 + E7777 was more effective than the combination of anti-PD-1+anti-CTLA-4 dual checkpoint blockade therapy in the “cold” 4T1 breast cancer model, which is characterized by strong myeloid cell-mediated immunosuppression and is typically refractory to T cell checkpoint inhibitors. This evidence concerns the gene PDCD1 and breast cancer.