STAT3 and hepatocellular carcinoma: In vivo and in vitro assays showed Oxysophocarpine sensitized the anti‐Lag‐3 immunotherapy effect against HCC by decreasing FGL1 expression through downregulating IL‐6‐mediated JAK2/STAT3 signaling, whereas Oxysophocarpine had a little effect of CD8+ T cells cytotoxicity function against HCC cells with TIGIT, PD‐1, or Tim‐3 blockade.