This study is a multi-center observational real-world study, with a total of 500 patients planned to be enrolled. This study is divided into two cohorts: the triple-negative breast cancer (TNBC) cohort and the hormone receptor-positive/human epidermal growth factor receptor 2-negative breast cancer (HR+/ HER2-BC) cohort. The aim of this study is to assess the efficacy and safety of Sacituzumab Tirumotecan (SKB264) monotherapy or combination therapy in patients with unresectable locally advanced, recurrent or metastatic HER2-negative breast cancer in the real-world setting.