ERBB2 and breast neoplasm: HR+/Her2- breast tumors are considered to have an “immunologically cold” microenvironment, which may predict low responsiveness to monotherapy with immune checkpoint inhibitors and the clinical hypothesis in the trial is that just like the observations in the pre-clinical models and TNBC patients in the clinic, the combination of Imprime/pembrolizumab will be able to reprogram the immunosuppressive microenvironment and allow increased trafficking of activated T cells in these patients as well.