For the hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) subtype of breast cancer, although surgical, radiotherapy, and endocrine treatments have shown better survival, this subtype has a relatively poor response to neoadjuvant chemotherapy and immunotherapy, with an approximately pCR of 20%. The low immunogenicity result in suboptimal pCR and objective response rates for this group. Therefore, there is an urgent need to explore new, highly effective, and low-toxicity treatment strategies to further improve the efficacy of HR+/HER2- breast cancer. Radiotherapy has systemic immune regulatory effects by promoting the release of antigens from tumor cells, enhancing T-cell infiltration, and directly killing tumor cells. Therefore, this study aims to investigate the efficacy and safety of chemotherapy combined with PD-1 inhibitor and different radiotherapy fractionations in the neoadjuvant treatment of HR+/HER2- breast cancer.