The purpose of the study is to address the following hypotheses: the PD-1 inhibitor Sintilimab 200mg for intravenous (IV) administration will be given together with three-week epirubincin, cyclophosphamide (EC) × 4 treatments from the second cycle followed by weekly nab-paclitaxel x12 treatments or three-week nab-paclitaxel x4 treatments. This regimen will induce higher pathologic complete response (pCR) rate in triple negative breast cancer than historical pCR rates (30-40%) observed with chemotherapy alone.

Inclusion Criteria:

• Newly diagnosed histologically confirmed stage I-III, ER, PR and HER2 negative invasive breast cancer as defined by the ASCO CAP guidelines for whom systemic chemotherapy would be indicated based on physician judgment following standard NCCN practice guidelines.

Exclusion Criteria:

• Patients for whom anthracycline, nab-paclitaxel or antibody therapies are contraindicated.