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Poor clinical outcome in cancer patients is associated with the presence of cancer-associated fibroblasts (CAFs). However, fibroblasts are heterogenous and can have different functions, and whether CAFs directly interact with and impact T cells in the tumor microenvironment remains to be determined. Cremasco and Astarita et al. show that two populations of FAP⁺ mesenchymal stromal cells exist in breast cancer tumors from humans and mice: those that express podoplanin (PDPN+ CAFs) and those that do not (cancer-associated pericytes; CAPs). Each population has a distinctive gene signature and localization within tumors, and FAP⁺PDPN⁺ CAFs were shown to suppress T cells, whereas FAP⁺PDPN⁻ CAPs were not immunosuppressive. These data highlight how different FAP⁺ stromal cell populations can modulate the breast cancer tumor microenvironment. Read more in this issue on page 1472. Original image from Supplementary Fig. S1E. Artwork by Lewis Long.