Efficacy and Safety of Multimodal Ablation Combined With PD-1 Monoclonal Antibody, Lenvatinib and TACE in the Treatment of Unresectable Primary Hepatocellular Carcinoma: A Single-Arm, Single-Center Clinical Study

Inclusion Criteria: 1. Age 18-80 years, regardless of gender. 2. Clinically or pathologically confirmed HCC. 3. CNLC stage IIb-IIIa, deemed unresectable after multidisciplinary evaluation. 4. Having radiologically evaluable, untreated target lesions for ablation, with the largest diameter of the target tumor \>5 cm. 5. Patients who have not undergone systemic chemotherapy, targeted therapy, or immunotherapy for hepatocellular carcinoma, or those who have been evaluated as SD (stable disease) or PD (progressive disease) after treatment.. 6. ECOG PS 0-1 and an expected survival \>3 months. 7. Child-Pugh score ≤7. Exclusion Criteria: 1. Child-Pugh class C liver dysfunction. 2. Tumor thrombus in the main portal vein or hepatic vein. 3. Extensive metastatic disease with an expected survival \<3 months. 4. Severe dysfunction of major organs (liver, kidney, heart, lung, or brain). 5. History of esophageal/gastric variceal bleeding within the past month. 6. History of other malignancies. 7. Last anti-tumor therapy (e.g., radiotherapy, systemic chemotherapy, or local treatment) within \<1 month. 8. Active infection; HBV co-infection (HBV DNA ≥2000 IU/mL or ≥10⁴ copies/mL unless reduced by one log after antiviral therapy); HCV co-infection requiring guideline-directed antiviral treatment; HIV infection; or biliary tract inflammation. 9. History of organ transplantation or hepatic encephalopathy. 10. Uncorrectable coagulation disorders. 11. Refractory massive ascites, pleural effusion, or cachexia. 12. Pregnancy, impaired consciousness, or inability to comply with treatment. 13. High tumor burden (sum of the largest liver lesion diameter and number of liver lesions \>12). 14. Any other condition deemed unsuitable by investigators that may affect study participation.