During an antitumor immune response, IFN‐I or DNA leaked from tumor cells also provoked IFN‐I signaling in immune cells, especially DCs, to form a positive feedback loop of such signaling.[33] Indeed, DCs cocultured with Smad4KO PDAC cells, but not WT cells, exhibited upregulation of Ifnα and Ifnβ expression (Figure 5F), and anti‐IFNAR1 pretreatment abolished such effect (Figure 5G). Here, IFNB1 is linked to neoplasm.