STAT3 and neoplasm: Importantly, by blocking IFN-γ-driven PD-L1 upregulation via suppression of STAT3, two flavonoids (baicalein and baicalin) restored T cells’ capacity to kill hepatocellular carcinoma (HCC) cells in vitro and induced more significant tumor regression in immunocompetent BALB/c mice than in BALB/c-nu/nu mice that lack T cells, indicating an essential role of T cells in these therapies [111].