Hand-drawn picture of interactions between PD-L1, Met, and IL10. (a) Met protein structure: Met is a heterodimer consisting of an extracellular alpha chain, and a beta chain that spans the membrane. The Met receptor has three functionally distinct domains, including the extracellular, transmembrane, and intracellular domain. The intracellular domain functions in three channels, including a region adjacent to the membrane-proximal intracellular domain, a tyrosine kinase catalytic structure with tyrosine kinase activity domain, and a C-terminal domain that interacts with a variety of downstream signaling molecules. (b) Dynamic interactions between PD-L1, Met, and IL10. The overexpression of PD-L1 upregulates the expression of IL10 in LIHC via a positive feedback loop while IL10 downregulates the expression of PD-L1 in LIHC via a negative feedback loop. (c) IL10 acts on the HGF (hepatocyte growth factor)/Met signaling pathway, thereby affecting its downstream Akt and MAPK signaling pathway before downregulating the PD-L1 expression.