When analyzing an in vivo murine breast tumor model with a deficient activation of CAFs due to Snail1 depletion, we realized that the total number of macrophages in mammary gland tumors was not different in both conditions but Snail1‐depleted tumors had a misbalanced polarization, with more MHCII‐high, classically activated macrophages. Here, SNAI1 is linked to breast neoplasm.