I. To compare invasive disease-free survival (IDFS) of patients with triple-negative breast cancer (TNBC) who have either >= 1 cm residual invasive breast cancer and/or positive lymph nodes (> ypN+) after neoadjuvant chemotherapy randomized to receive 1 year of MK-3475 (pembrolizumab) adjuvant therapy compared to no MK-3475 (pembrolizumab), in both the entire study population and also in the PD-L1 positive subset.