TGF-β1 in M2 macrophages induces EMT and gemcitabine resistance in CCA through the APKC-γ-mediated NF-κB signaling pathway. At this time, the secretion of CCL5 in CCA cells increases, thereby regulating the recruitment and polarization of macrophages. The gene discussed is TGFB1; the disease is cholangiocarcinoma.