Consistently, a positive association between the apCAFs score and Treg score was observed in the TCGA pancreatic cancer cohort (p = 0.0036, Figure 5F), which was further validated in another pancreatic tumor cohort (p = 0.00027, Figure S12, Supporting Information).[15] Taken together, our results suggested that the anti‐MSLN antibody could reduce the amount of apCAFs in pancreatic cancer and convert Naive T Cells to Treg cells, thereby enhancing the infiltration and anti‐tumor ability of neoantigen vaccine induced CD8+ T cells. This evidence concerns the gene MSLN and familial pancreatic carcinoma.