Abstract: Immunotherapy is deemed as one of the most promising anti-tumor treatments. However, weak immunogenicity and suppressed immune reactivity largely constrain the application of immunotherapy in breast cancer(BC). In the past few decades, more and more studies have found that tumor immune markers such as programmed death receptor-1(PD-L1) are involved in certain aspects of tumor immunity,promoting the formation of immune suppression and thus affecting the effect of immunotherapy. Tumor immune biomarkers promote the development of precise and individualized immunotherapy of BC as well as its innovative clinical applications by predicting, monitoring and regulating the balance of tumor immune response. This article reviews the key starting and ending of anti-tumor immunity(immune recognition and killing), the mechanism of tumor immune markers and their related clinical research and application, in order to provide some reference for further research on BC immunotherapy.