To evaluate the efficacy and safety of a multimodal therapeutic approach involving transarterial chemoembolization (TACE) in conjunction with helical iodine-125 (I-125) seed implant, lenvatinib, and programmed cell death-1(PD-1) inhibitors for hepatocellular carcinoma (HCC) complicated by main portal vein tumor thrombus (MPVTT). The gene discussed is PDCD1; the disease is hepatocellular carcinoma.