ARG1 and neoplasm: IL-7 alone had no effect on BMDM polarization (Supplementary Fig. S4A, B), but it further upregulated the expression of Il10 and Arg1 in macrophages co-cultured with WT tumor cells (Fig. 4E); no such response was observed in macrophages co-cultured with Il7r-KO tumor cells (Supplementary Fig. S4C).