Breast cancer is the most commonly diagnosed cancer with over 2.3 million new cases diagnosed and 685,000 deaths worldwide in 2020. Triple-negative breast cancer (TNBC), which is characterized by high invasiveness, high metastatic potential, poor prognosis, and proneness to relapse, accounts for approximately 15-20% of all cancer types. Despite the numerous treatments available, it is reported that TNBC patients develop resistance to chemotherapeutic drugs frequently and have a relatively low response rate to immunotherapy due to insufficient T-lymphocyte infiltration. In this study, human breast cancer cells MDA-MB-231 are treated with increasing concentrations and treatment durations of Oxaliplatin to investigate the anti-cancer potential of Oxaliplatin. A xenograft assay with MDA-MB-231 is further pursued to test the efficacy of the combination treatment of Oxaliplatin and Pembrolizumab, a monoclonal anti-PD-1 antibody. For the xenograft assay, tumor growth is measured after receiving Oxaliplatin followed by Pembrolizumab. Immunogenetic cell death (ICD) in vitro is measured by flow cytometry of calreticulin (CRT) and Western blot of high mobility group protein B1 (HMGB1) in supernatant; cytotoxic T-lymphocyte infiltration is measured in the xenograft model via flow cytometry using T-cell markers from cells retrieved from the tumor mass; tumor growth is measured using the digital caliper. The result of this study provides insight into the anti-cancer potential of Oxaliplatin and Pembrolizumab combination treatment in TNBC, providing a reference for future studies of combining chemotherapy and immunotherapy in treating breast cancer.