ObjectiveTo summarize the mechanism of action of programmed cell death protein 1 (PD-1)/programmed cell death ligand-1 (PD-L1) inhibitors, the application in breast cancer in recent years and the advances in the study of their bio-markers of effects. MethodRelevant literatures on PD-1/PD-L1 inhibitors and the study in the field of breast cancer were reviewed and summarized.ResultsIn recent years, the monotherapy of immune checkpoint inhibitors represented by PD-1/PD-L1 inhibitors or in combination with other therapies had brought new hope for patients with breast cancer especially triple-negative breast cancer (TNBC). However, only a small number of patients could benefit from breast cancer immunotherapy. The current researchers think that the efficacy of these drugs is related to PD-L1 expression in tumor tissue, tumor mutation burden (TMB), high level of microsatellite instability (MSI-H) and deficient mismatch repair (dMMR).ConclusionBreast cancer can benefit from the immunotherapy of PD-1/PD-L1 inhibitors, but formulating personalized medicine model, finding biomarkers that can predict efficacy and selecting patients with breast cancer who can benefit from it for targeted therapy are the new requirements in the new era of breast cancer immunotherapy.