Atezolizumab was approved to be applied to treating patients with inoperable triple⁃negative breast malignant tumor which was assured to be PD⁃L1 positive by tissue biopsy. Generally, the expression of PD⁃1/PD⁃L1 in the tissue microenvironment is used as an indication of whether to use this inhibitor in clinical practice. A number of clinical studies have shown that the expression of PD⁃1/PD⁃L1 can imply the tumor staging, prognosis, and reflect the immune status of the individual, as well as the sensitivity and efficacy of the immune checkpoint inhibitors. However, tissue biopsy can′t monitor the dynamic change of the expression of immune checkpoint molecules to Adjust clinical medication relevantly. As a result the use of other forms of PD⁃1/PD⁃L1 detection in peripheral blood as an alternative to histopathological examination has become a research focus. This article will briefly review the current detection methods of PD⁃1 and PD⁃L1 in the peripheral blood in patients with breast tumors, including plasma soluble PD⁃1/PD⁃L1 (sPD⁃1/sPD⁃L1); exosomal PD⁃1/PD⁃L1; circulating tumor cells PD⁃1/PD⁃L1 and circulating lymphocytes PD⁃1/PD⁃L1, point out the prospect and challenge in breast cancer in this field and provide new directions for new clinical PD⁃1/PD⁃L1 detection methods.