Brief Summary

Eligible participants will undergo baseline procedures including research bloodwork, MRI and PET scan. Participants will then be treated with one cycle of paclitaxel, carboplatin and pembrolizumab. At the end of Cycle One (C1D15 +7days) patients will undergo repeat procedures (bloodwork, PET scan), and then continue with treatment for an additional three cycles. At the end of treatment patients will undergo repeat MRI. Patients achieving a cCR will be encouraged to proceed with surgery. Patients with clinical residual disease (RD) on MRI will be recommended a biopsy, if feasible and felt to be clinically ndicated, and proceed with “rescue” neoadjuvant doxorubicin and cyclophosphamide (AC) with pembrolizumab for four additional cycles, and then proceed with surgery. Tissue will be collected from the surgical product. Patients achieving a pCR may proceed with adjuvant pembrolizumab per standard of care, and treating physician discretion. Patients with pathological RD may proceed with “rescue” adjuvant AC with pembrolizumab for four additional cycles (if not received neoadjuvantly), per treating physician discretion. They may also receive adjuvant capecitabine or olaparib as indicated and per treating physician discretion.