These data show that IL-38 regulates Xcl1 secretion from γδ T cells, and are consistent with the view that IL-38 blockade propagates cDC1 recruitment into tumors by γδ T cell-derived Xcl1, while cDC1 in turn activate CD8+ T cells via Notch signaling to improve tumor immune control (online supplemental figure S4). Here, XCL1 is linked to neoplasm.