TGF-β1, a cytokine produced by tumor cells, induces Tregs heterogeneity in the TME, shapes an environment conducive to proliferation, anti-apoptosis and angiogenesis for tumor cells, makes tumor cells immune escape and promotes the development of CCA, while GCA (e.g., gemcitabine, and albumin-bound paclitaxel neoadjuvant therapy) can prevent the mechanism 59. Here, TGFB1 is linked to cholangiocarcinoma.