ARG1 and hepatocellular carcinoma: 1. Promote pro-inflammatory M1 polarization (↑CD86, iNOS; ↓CD163, ARG1) via histone acetylation-driven ACC1 transcription and increase fatty-acid synthesis;2. M1 macrophages enhance CD8+ T cell function (↑IFN-γ, granzyme B), increasing cytotoxicity against hepatocellular carcinoma (HCC) cells.