To the best of our knowledge our study is the first using single cell mass cytometry to show the immunomodulatory effect of cisplatin in the 4T1 murine model of metastatic triple negative breast cancer via downregulation of immature myeloid cells and upregulation of CD62L+ B- and T-cells and IFN-γ+ peripheral myeloid cells. Here, SELL is linked to triple-negative breast carcinoma.