MTR and neoplasm: First, CAFs and Mφs are the most abundant cellular populations within the breast TME.[26] Second, the reciprocal communication between CAFs and Mφs aids in the establishment of an immunosuppressive milieu.[26a] Though a clear perspective exists on the collaborative roles of CAFs and Mφs in driving tumor growth, the synergistic effect of tumor cells, CAFs, and Mφs has not been studied at the single‐cell level using well‐controlled ex vivo model systems.