TGFB1 and pulmonary fibrosis: Overexpression of PDL1 can inhibit autophagy of fibrosis-related cells through the PI3K/AKT/mTOR signal pathway, up regulate TGF-β and fibrosis-related factor a-SMA (90–92); fourthly, elevated PDL1 expression in pulmonary fibroblasts impedes adaptive immunity, fostering pulmonary fibrosis.