Study of Sacituzumab Govitecan-hziy and Pembrolizumab Versus Treatment of Physician's Choice in Patients With Triple Negative Breast Cancer Who Have Residual Invasive Disease After Surgery and Neoadjuvant Therapy (ASCENT-05/AFT-65 OptimICE-RD/GBG 119/NSABP B-63)

Key Inclusion Criteria:

• Age > 18 years, with residual invasive triple negative breast cancer (TNBC) in the breast or lymph nodes after neoadjuvant therapy and surgery:

• TNBC criteria for the study is defined as estrogen receptor (ER) and progesterone receptor (PR) ≤ 10%, human epidermal growth factor receptor 2 (HER2)-negative per American Society of Clinical Oncology and College of American Pathologists (ASCO/CAP) guidelines (immunohistochemistry (IHC) and/or in situ hybridization (ISH)).
• Adequate excision and surgical removal of all clinically evident of disease in the breast and/or lymph nodes and have adequately recovered from surgery.
• Submission of both pre-neoadjuvant treatment diagnostic biopsy and resected residual invasive disease tissue.
• Eastern Cooperative Oncology Group (ECOG) performance status 0-1.
• Individuals must have received appropriate radiotherapy aligned with local/institutional practice and have recovered prior to starting study treatment.
• Adequate organ function.

Key Exclusion Criteria:

• Stage IV (metastatic) breast cancer as well as history of any prior (ipsi- or contralateral) invasive breast cancer.
• Prior treatment with another stimulatory or coinhibitory T-cell receptor agent (eg, cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), OX-40, cluster of differentiation 137 (CD137), prior treatment with any HER2-directed agent, prior endocrine therapy for > 4 weeks or planned concurrent endocrine therapy while receiving on-study treatment.
• Evidence of recurrent disease following preoperative therapy and surgery.
• Prior treatment with topoisomerase 1 inhibitors or antibody-drug conjugates (ADCs) containing a topoisomerase inhibitor.
• Individuals with germline breast cancer gene (BRCA) mutations.
• Myocardial infarction or unstable angina pectoris within 6 months of enrollment or history of serious ventricular arrhythmia (ie, ventricular tachycardia or ventricular fibrillation), high-grade atrioventricular block, or other cardiac arrhythmias or Left ventricular ejection fraction (LVEF) of < 50%
• Active serious infections requiring anti-microbial therapy.

Note: Other protocol defined Inclusion/Exclusion criteria may apply.