Adjuvant PVX-410 Vaccine and Durvalumab in Stage II/III Triple Negative Breast Cancer

This research study is a Phase Ib clinical trial, which tests the safety of an investigational intervention and also tries to better understand how the investigational intervention affects the body. "Investigational" means that the intervention is being studied. The FDA (the U.S. Food and Drug Administration) has not approved PVX-410 and Durvalumab as a treatment for any disease. * Durvalumab is a protein that affects your immune system by blocking the PD-L1 pathway. The PD-L1 pathway controls the body's natural immune response, but tumors can interrupt this pathway and partially resist or escape the immune system. By blocking the PD-L1 pathway, Durvalumab may help the immune system identify and catch tumor cells. * PVX-410 is an investigational vaccine that is being developed to treat multiple myeloma and triple negative breast cancer. * In this research study, the investigators are studying the body's immune response to the PVX-410 study vaccine in combination with Durvalumab. This study will help researchers understand if the vaccine and Durvalumab can work together to help the body's immune system recognize triple negative breast cancer. The investigators are also studying the safety of the PVX-410 vaccine alone and together with the Durvalumab.