Inclusion Criteria:

          -  Non-metastatic operable Stage II-III breast cancer

          -  Histologically documented TNBC (Triple Negative Breast Cancer)

          -  Confirmed tumor PD-L1 evaluation as documented through central testing of a
             representative tumor tissue specimen

          -  Adequately excised: Patients must have undergone either breast-conserving surgery or
             mastectomy/nipple- or skin-sparing mastectomy

          -  Adequate hematologic and end-organ function

          -  For women of childbearing potential: agreement to remain abstinent (refrain from
             heterosexual intercourse) or use contraceptive measures

          -  For men: agreement to remain abstinent (refrain from heterosexual intercourse) or use
             contraceptive measures and agreement to refrain from donating sperm.

          -  No more than 8 weeks (56 days) may elapse between definitive breast surgery and
             randomization.

          -  Representative formalin-fixed, paraffin embedded (FFPE) tumor specimen from surgical
             resection in paraffin blocks (preferred) or at least 25 unstained slides.

        Exclusion Criteria

          -  Prior history of invasive breast cancer

          -  For the currently diagnosed breast cancer, any previous systemic anti-cancer treatment
             (e.g., neoadjuvant or adjuvant), including, but not limited to, chemotherapy,
             anti-HER2 therapy.

          -  Previous therapy with anthracyclines or taxanes for any malignancy

          -  Cardiopulmonary dysfunction

          -  Prior malignancies within 5 years prior to randomization, with the exception of those
             with a negligible risk of metastasis or death and treated with expected curative
             outcome

          -  Active or history of autoimmune disease or immune deficiency

          -  History of idiopathic pulmonary fibrosis, organizing pneumonia, drug-induced
             pneumonitis, idiopathic pneumonitis, or evidence of active pneumonitis on screening
             chest computed tomography (CT) scan

          -  Urinary outflow obstruction

          -  Active tuberculosis

          -  Major surgical procedure other than for diagnosis within 4 weeks prior to initiation
             of study treatment or anticipation of need for a major surgical procedure during study
             treatment or within 5 months following the last dose of Atezolizumab (for patients
             randomized to Atezolizumab)

          -  Prior allogeneic stem cell or solid organ transplant

          -  Treatment with systemic immunosuppressive medications within 2 weeks prior to
             initiation of study treatment or anticipation of need for systemic immunosuppressive
             medication during the study