Hepatocellular carcinoma (HCC) is a major global health issue with limited treatment options and poor prognosis. Recent advances in immunotherapy, particularly immune checkpoint inhibitors (ICIs), have significantly improved systemic treatment outcomes for HCC. Combination therapies based on ICIs are now the main trend, with dual checkpoint blockade using durvalumab and tremelimumab showing promise for advanced HCC. However, most HCC patients still benefit little from these treatments. Understanding the immunological mechanisms and exploring new strategies to enhance immunotherapy efficacy are critical. This review summarizes recent progress in immunosuppressive tumor microenvironment (TME) characteristics, established immunotherapy strategies like ICIs, and emerging approaches such as chimeric antigen receptor T cells, personalized neoantigen vaccines, oncolytic viruses, and bispecific antibodies. The TME of HCC is immunosuppressive, with various cell types, cytokines, and components contributing to tumor immune evasion. Tumor-associated macrophages (TAMs) and tumor-associated neutrophils (TANs) play key roles in immunosuppression, while dendritic cells (DCs) are crucial for antigen presentation. Innate lymphoid cells (ILCs), including NK cells, ILC1s, ILC2s, and ILC3s, also influence tumor immunity. T cells, particularly CD4+ and CD8+ T cells, often exhibit a dysfunctional or exhausted phenotype in HCC. B cells and non-hematopoietic stromal cells, such as cancer-associated fibroblasts (CAFs), contribute to immunosuppression and tumor progression. ICIs, particularly targeting PD-1/PD-L1 and CTLA-4, are the most widely used immunotherapies for HCC. Combination therapies with anti-VEGF agents, TKIs, or other immunotherapies have shown improved efficacy. The IMbrave150 trial demonstrated that atezolizumab plus bevacizumab significantly improved survival in advanced HCC. The LEAP-002 trial showed that lenvatinib plus pembrolizumab improved progression-free survival. The HIMALAYA trial confirmed the efficacy of durvalumab plus tremelimumab in unresectable HCC. Immunotherapy-based perioperative treatments, including adjuvant, neoadjuvant, and downstaging conversion therapies, are increasingly important in HCC management. These approaches aim to improve surgical outcomes and reduce recurrence. However, challenges remain in identifying predictive biomarkers, overcoming drug resistance, and managing systemic toxicity. Future research should focus on optimizing immunotherapy combinations, enhancing TME remodeling, and developing novel strategies to improve HCC treatment outcomes.Hepatocellular carcinoma (HCC) is a major global health issue with limited treatment options and poor prognosis. Recent advances in immunotherapy, particularly immune checkpoint inhibitors (ICIs), have significantly improved systemic treatment outcomes for HCC. Combination therapies based on ICIs are now the main trend, with dual checkpoint blockade using durvalumab and tremelimumab showing promise for advanced HCC. However, most HCC patients still benefit little from these treatments. Understanding the immunological mechanisms and exploring new strategies to enhance immunotherapy efficacy are critical. This review summarizes recent progress in immunosuppressive tumor microenvironment (TME) characteristics, established immunotherapy strategies like ICIs, and emerging approaches such as chimeric antigen receptor T cells, personalized neoantigen vaccines, oncolytic viruses, and bispecific antibodies. The TME of HCC is immunosuppressive, with various cell types, cytokines, and components contributing to tumor immune evasion. Tumor-associated macrophages (TAMs) and tumor-associated neutrophils (TANs) play key roles in immunosuppression, while dendritic cells (DCs) are crucial for antigen presentation. Innate lymphoid cells (ILCs), including NK cells, ILC1s, ILC2s, and ILC3s, also influence tumor immunity. T cells, particularly CD4+ and CD8+ T cells, often exhibit a dysfunctional or exhausted phenotype in HCC. B cells and non-hematopoietic stromal cells, such as cancer-associated fibroblasts (CAFs), contribute to immunosuppression and tumor progression. ICIs, particularly targeting PD-1/PD-L1 and CTLA-4, are the most widely used immunotherapies for HCC. Combination therapies with anti-VEGF agents, TKIs, or other immunotherapies have shown improved efficacy. The IMbrave150 trial demonstrated that atezolizumab plus bevacizumab significantly improved survival in advanced HCC. The LEAP-002 trial showed that lenvatinib plus pembrolizumab improved progression-free survival. The HIMALAYA trial confirmed the efficacy of durvalumab plus tremelimumab in unresectable HCC. Immunotherapy-based perioperative treatments, including adjuvant, neoadjuvant, and downstaging conversion therapies, are increasingly important in HCC management. These approaches aim to improve surgical outcomes and reduce recurrence. However, challenges remain in identifying predictive biomarkers, overcoming drug resistance, and managing systemic toxicity. Future research should focus on optimizing immunotherapy combinations, enhancing TME remodeling, and developing novel strategies to improve HCC treatment outcomes.