STAT3 and hepatocellular carcinoma: The PI3K/Akt/mTOR pathway is a core driver of PD-L1 expression in HCC, primarily by activating downstream transcription factors like hypoxia-inducible factor-1α (HIF-1α), nuclear factor-κB (NF-κB), and signal transducer and activator of transcription 3 (STAT3) to promote the transcription of CD274 (the gene encoding PD-L1) 82.