This trial is a Phase II study. The purpose of this study is to evaluate the efficacy, safety, and pharmacokinetics of HB0025 administered with chemotherapy in participants with locally advanced or metastatic triple-negative breast cancer (TNBC) who have not received prior systemic therapy for metastatic breast cancer (mBC).

Inclusion Criteria:

1. Signed informed consent form
2. Metastatic or locally advanced, histologically documented TNBC (absence of HER2, ER, and PR expression)
3. No prior systemic therapy for inoperable locally advanced or metastatic TNBC
4. ECOG performance status of 0 or 1
5. Life expectancy ≥ 12 weeks
6. Measurable disease, as defined by RECIST v1.1

Exclusion Criteria:

1. History of severe allergic diseases, allergic history of serious drugs (including unlisted test drugs) or known allergic to any component of this test drug;
2. Previously received any antibody or inhibitor therapy targeting PD-1/PD-L1 or VEGF;
3. Uncontrollable or symptomatic central nervous system (CNS) metastasis;
4. Pregnancy or lactation;
5. Those who have active infection
6. Known history of allogeneic organ transplantation or allogeneic hematopoietic stem cell transplantation

n