Inclusion Criteria:  Histological diagnosis of metastatic or locally advanced breast cancer; Histologically proven diagnosis of ER-positive, HER2-negative; At least 1 line of endocrine therapy in the metastatic or advanced setting that had progressed or intolerance; ≤ 2 lines of chemotherapy for metastatic or advanced disease; Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0 or 1; Expected survival of more than 3 months.  Exclusion Criteria:  All patients in monotherapy and or in combination wih phase who are known allergic to HRS8807 or SHR6390 ingredient; Presence of symptomatic metastatic visceral disease ; Patients with known active brain metastases; Clinically serious cardiovascular disease; Abnormal electrocardiographic (ECG) with clinical significancy by investigator judgement; Abnormal thyroid function laboratory results; Active infection or unexplained fever >38.5℃ during screening period or on the day of the first dose.