Although BC is not classically considered to be immunoresponsive, we are among the first to report a detailed study on the dynamic breast immune environment where HMD tissue is associated with increased infiltration of innate immune cells (macrophages, DC), adaptive immune cells (B cells, CD4 T cells), as well as activated T cells (PD-1 expression) and protumor Th2 polarization (elevated IL-6 and IL4 secretion). Here, PDCD1 is linked to breast cancer.