STAT3 and hepatocellular carcinoma: HCC-CAFs attract peripheral blood neutrophils through the SDF1a/CXCR4 pathway. HCC-CAF-derived IL-6 was responsible for the STAT3 activation of neutrophils. Following STAT3 activation, PDL1 is expressed at the surface of the neutrophil. Then neutrophils impaired T-cell function through the PD1/PDL1 signaling pathway.