The extracellular 2′3′‐cGAMP level was higher in the co‐culture system with STF‐1623 treatment than that without STF‐1623 treatment (Figure 4E), which indicates that the cGAMP hydrolase activity of tumor exosomal ENPP1 was blocked by STF‐1623. Here, ENPP1 is linked to neoplasm.