These observations were related to a decreased cDC1-related transcriptional signature in the tumor and an increased Wnt/β-catenin response signature, similar to observations previously reported by Spranger and colleagues in melanoma, showing that β-catenin-mediated restriction in cDC1 recruitment to the tumor stood in the way of effective PD-1 blockade (56). Here, MPPE1 is linked to melanoma.