Recently, PD-L1/PD-1 axis blockade has been suggested as a potent strategy against multiple malignancies, including non-small cell lung cancer (NSCLC), hepatocellular carcinoma (HCC) and breast cancer (BC) [6–9], and this highlights the importance of PD-L1 in promoting tumor progression through immunosuppression. Here, PDCD1 is linked to breast cancer.