CD44 and neoplasm: To identify communication patterns used by MBC tumor-infiltrating Treg cells, we predicted receptor–ligand interactions that may mediate crosstalk between Treg cells and other cell states in intratumoral hubs using CellPhoneDB56 (Fig. 4h, Supplementary Fig. 14b,c and Methods), revealing immunosuppressive pathways related to FGF2, FGFR1 and CD44 expression involved in MBC.