Recent findings suggest that in vivo cross‐presentation of tumor‐derived antigens is mainly dependent on cDC1s, which often show CD103 expression in tumor tissues.[25] Indeed, the levels of tumor‐infiltrating CD11c+CD103+ cells and activated DCs (gated as CD40+CD11c+ and MHC‐II+CD11c+) were both increased in Smad4KO PDAC (Figure3A–C; Figure S3A, Supporting Information) and KPC‐1199 tumors (Figure S3B,C, Supporting Information), suggesting enhanced intratumoral DC activation. This evidence concerns the gene ITGAE and neoplasm.