Additionally, compared with the normal breast tissues, we found significant increases in the frequency of memory B cells, activated memory CD4+ T cells, regulatory T cells (Tregs), M0 and M1 macrophages, activated dendritic cells, and activated mast cells (the primary tumor‐infiltrating immune cells in BRCA), and pronounced decreases in the frequency of CD8+ T cells, activated NK cells, and macrophages M2 (Figure 3B). Here, CD4 is linked to neoplasm.