CD8A and hepatocellular carcinoma: In HCC, A. muciniphila suppresses tumor growth by remodeling bile acid metabolism (elevating tauroursodeoxycholic acid) and glycerophospholipid pathways, which sustain IFN-γ and IL-2 production by CD8+ T cells (224, 260); it also reinforces gut barrier integrity, reduces systemic inflammation, and induces IL-12 secretion by DCs, further enhancing antitumor immunity (261).