M2 macrophages are known to promote the expansion of Th2 cells and regulatory T cells in PDAC, whereas M1 macrophages recruit Th1 cells and enhance anti‐tumor cytotoxic T lymphocyte activity.[59, 60] Our study demonstrates that Ccn1‐deficient tumor cells induce greater macrophage infiltration while maintaining the M1 phenotype. The gene discussed is CCN1; the disease is neoplasm.