CD274 and neoplasm: IHC staining using PDAC patient-derived tumor tissues revealed that PD-L1-expressing CAFs were negatively correlated with patient prognosis and positively correlated with tumor fibrosis (r = −0.6672, p = 0.001; r = 0.7805, p < 0.001, respectively) (Fig. 2l–n; Supplementary Fig. 2h, i).