Combined blockade of PD-L1, CD47, and IL-6 signaling can significantly inhibit bleomycin-induced pulmonary fibrosis in mice by activating adaptive immune response and macrophage phagocytic activity, suggesting that PD-L1 mediated pro-fibrotic response may be the common mechanism of pulmonary fibrosis induced by different factors (154). Here, IL6 is linked to pulmonary fibrosis.