A Clinical Study to Evaluate the Efficacy and Safety of JS212 Monotherapy or Combination Therapy in Recurrent or Metastatic Triple-negative Breast Cancer(TNBC)

Inclusion Criteria: 1. Male or female age 18-70 years old; 2. Voluntary participation in clinical study; 3. Histologically confirmed unresectable, locally advanced or metastatic triple-negative breast cancer(absence of HER2, ER, and PR expression); 4. No prior systemic antitumor therapy for locally advanced or Metastatic TNBC（cohort expansion period); only one line of prior systemetic treatment for locally advanced or metastatic TNBC; 5. Adequate organ function; 6. ECOG performance status of 0 or 1; 7. Life expectancy 12 weeks; 8. Measurable disease, as defined by RECIST v1.1; Exclusion Criteria: 1. Untreated or active central nervous system (CNS) metastases; 2. Uncontrolled pleural effusion, pericardial effusion or ascites; 3. Tumor encasement of important vessels or significant necrosis and cavitation that may cause a risk of hemorrhage; 4. History of significant bleeding tendency or severe coagulation disorder; 5. Uncontrolled hypertension; 6. Active autoimmune diseases requiring systemic treatmen within 2 years prior to the first dose; 7. History of interstitial lung disease or previous Noninfectious pneumonitis treated with corticosteroids, or evidence of active Pneumonia in radiology on screening period; 8. History of immunodeficiency. Presence of active tuberculosis, hepatitis B, or hepatitis C; 9. Severe cardiovascular disease; 10. Serious infection (CTCAE 6.0 Grade\>2) within 28 days prior to the first dose of study drug; 11. Previous treatment of any anti-VRGF drugs targeting VEGF (part 1) or ADC drugs targeting EGFR and/or HER3; 12. History of another malignancy within 5 years before the first dose of study drug; 13. Not suitable to receive study treatment for other conditions as per investigator;