A Phase 3 Study Comparing Carelizumab Plus Nab-paclitaxel and Apatinib, Carelizumab Plus Nab-paclitaxel, and Nab-paclitaxel in Patients With Advanced Triple Negative Breast Cancer.

Inclusion Criteria:

* ECOG Performance Status of 0-1.
* Expected lifetime of not less than three months
* Metastatic or locally advanced, histologically documented TNBC (absence of HER2, ER, and PR expression)
* Cancer stage: locally advanced or metastatic breast cancer; Locally advanced breast cancer not amenable to radical resection.
* No prior systemic antitumor therapy for metastatic triple-negative breast cancer.
* Adequate hematologic and organ function
* Measurable disease according to Response Evaluation Criteria in Solid Tumors v1.1 (RECIST v1.1)

Exclusion Criteria:

* Known central nervous system (CNS) disease.
* Previously received anti-VEGFR small molecule tyrosine kinase inhibitors or anti-PD-1/PD-L1 antibody.
* A history of bleeding, any serious bleeding events.
* Uncontrolled pleural effusion, pericardial effusion.
* Malignancies other than TNBC within 5 years prior to randomisation, or ascites requiring recurrent drainage procedures
* History of interstitial pneumonitis.
* Severe chronic or active infections in need of systemic antibacterial, antifungal, or antiviral treatment, including TB, etc.
* Prior allogeneic stem cell or solid organ transplantation.
* History of autoimmune disease
* Active hepatitis B or hepatitis C
* Pregnancy or lactation.
* Peripheral neuropathy grade ≥2.
* Participants with poor blood pressure control;
* Myocardial infarction incident within 6 months prior to randomisation;
* Treatment with systemic immunostimulatory agents within 4 weeks prior to randomisation
* Treatment with systemic immunosuppressive medications within 2 weeks prior to randomisation