Inclusion Criteria:

          -  Metastatic or locally-advanced, histologically documented TNBC (absence of HER2, ER,
             and PR expression)

          -  Have not previously received cytotoxic therapy for the treatment of unresectable
             locally-advanced breast cancer or metastatic breast cancer

          -  At least 6 months since prior treatment with curative intent and recurrence

          -  At least 1 tumor 10mm in diameter or greater OR lymph node of at least 15 mm in short
             axis

          -  Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1

          -  Able to provide biopsy tissue for biomarker analysis

          -  Meet baseline laboratory data criteria

        Exclusion Criteria:

          -  Prior immune-oncology therapy

          -  Pre-existing neuropathy of at least Grade 2

          -  History of carcinomatous meningitis or active central nervous system (CNS) metastases.
             Patients are eligible if CNS metastases are adequately treated and patients have
             neurologically returned to baseline (except for residual signs or symptoms related to
             the CNS treatment) for at least 4 weeks prior to enrollment. Patients must be off
             corticosteroids.

          -  Received prior radiotherapy within 2 weeks of start of study treatment or have not
             adequately recovered from prior radiotherapy

          -  Active autoimmune disease requiring systemic treatment within the past 2 years

          -  History of interstitial lung disease

          -  Current pneumonitis or history of pneumonitis requiring steroids