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Background The liver’s inherently immunosuppressive microenvironment presents a major barrier to effective immunotherapy for hepatocellular carcinoma (HCC). Although interleukin-10 (IL-10) has demonstrated antitumor activity in several cancer models, its therapeutic potential in HCC remains unclear. Here, we investigated whether liver-directed delivery of IL-10 using an adeno-associated virus vector (AAV-IL-10) could enhance antitumor immunity in HCC.Methods Syngeneic orthotopic and intrahepatic metastatic HCC mouse models were used to evaluate the effects of liver-directed AAV-IL-10 therapy. Tumor burden, immune cell infiltration, and functional activation were assessed by flow cytometry and related analyses.Results Liver-directed AAV-IL-10 treatment significantly reduced intrahepatic tumor burden and promoted robust infiltration of CD8 + T cells into the tumor microenvironment. AAV-IL-10 enhanced the functional activation of natural killer cells and CD8+ T cells, as reflected by increased expression of effector cytokines and cytotoxic molecules. Notably, AAV-IL-10 augmented the effector capacity of terminally exhausted CD8+ tumor-infiltrating lymphocytes and expanded a population of CD8+ T cells with a tissue-resident memory (Trm)-like phenotype. These Trm-like CD8+ T cells were liver-resident and persisted after tumor clearance. Importantly, the antitumor effects of AAV-IL-10 were confined to the liver and did not affect the growth of distant subcutaneous tumors.Conclusions Liver-directed AAV-IL-10 delivery overcomes local immunosuppression and enhances CD8 + T cell-mediated antitumor immunity in murine HCC models. These findings support targeted IL-10 delivery as a promising strategy to improve immunotherapy outcomes in liver cancer.