A Study of Tobemstomig + Nab-Paclitaxel Compared With Pembrolizumab + Nab-Paclitaxel in Participants With Previously Untreated, PD-L1-Positive, Locally-Advanced Unresectable or Metastatic Triple-Negative Breast Cancer

Inclusion Criteria: * Metastatic or locally advanced unresectable, histologically documented triple-negative breast cancer (TNBC) (absence of HER2-over-expression, ER, and PgR expression by local assessment) * HER2-low-status * Measurable disease per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 * If metastatic disease (Stage IV), measurable disease outside of the bone * No prior systemic therapy for metastatic or locally advanced unresectable TNBC * Tumor PD-L1 expression as documented through central testing of a representative tumor tissue specimen * Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1 * Adequate hematologic and end-organ function * Negative HIV test at screening, with the following exception: individuals with a positive HIV test at screening are eligible provided they are stable on anti-retroviral therapy, have a CD4 count ≥ 200/uL, and have an undetectable viral load * Negative hepatitis B surface antigen (HBsAg) test at screening * Positive hepatitis B surface antibody (HBsAb) test at screening, or a negative HBsAb at screening accompanied by either of the following: negative hepatitis B core antibody (HBcAb); positive HBcAb test followed by quantitative hepatitis B virus (HBV) DNA \< 500 IU/mL * Negative hepatitis C virus (HCV) antibody test at screening, or a positive HCV antibody test followed by a negative HCV RNA test at screening * Adequate cardiovascular function Exclusion Criteria: * Pregnancy or breastfeeding, …