Oñate and colleagues demonstrate that KITL expression in pancreatic stellate cells is crucial for maintaining the inherent tumor-suppressive function of the pancreatic microenvironment, and its loss enables pancreatic cancer development. This pivotal discovery not only reinforces the century-old hypothesis of natural microenvironmental tumor suppression but also highlights a promising therapeutic avenue whereby restoring KITL expression could reestablish the tumor-suppressive functions of pancreas-resident fibroblastic cells. See related article by Oñate et al., p. 913.