S1418/BR006: Testing Pembrolizumab (MK-3475) as Adjuvant Therapy for Triple-Negative Breast Cancer

The purpose of this study is to compare the usual approach (no more treatment, additional chemotherapy and radiation after surgery, or radiation alone after surgery) with any effects of receiving 1 year of treatment with pembrolizumab after surgery. This study will allow researchers to know whether treatment with pembrolizumab is better, the same or worse than the usual approach.