A Trial of HRS-6209-205 to Evaluate the Safety, Tolerability, Pharmacokinetics and Efficacy of HRS-6209 in Combination Therapy in Subjects With HR-Positive/HER2-Negative Cancer

To evaluate the Safety, Tolerability, Pharmacokinetics and Efficacy of HRS-6209 in Subjects with HR-Positive/HER2-Negative solid tumor.

Inclusion Criteria 1. Ability to understand the trial procedures and possible adverse events, voluntarily participate in the trial. 2. Adequate bone marrow and other vital organ functions 3. Adequate liver function tests 4. HR-positive or HER2-negative solid tumor patients Exclusion Criteria 1. Plan to receive any other anti-tumor therapy during the study. 2. Active brain metastases . 3. Have poorly controlled or severe cardiovascular disease, including (1) congestive heart failure. 4. Previous use of fulvestrant 5. clinically significant endometrial abnormalities, including but not limited to endometrial hyperplasia and dysfunctional uterine bleeding. 6. With uncontrollable chronic systemic complications (such as severe chronic lung, liver, kidney, or heart disease). 7. With acute or active tuberculosis infection requiring medication. 8. Pregnant or lactating women, or females planning to become pregnant During the study. 9. Known history of clinically significant liver disease, untreated active hepatitis (hepatitis B, defined as hepatitis B virus surface antigen \[HBsAg\] or hepatitis B core antibody \[HBcAb\] positive