PDCD1 and hepatocellular carcinoma: Therefore, we conducted this prospective, multicenter, phase 2 trial with a dual primary aim: first, to investigate the efficacy and safety of the sequential triple combination of lenvatinib, TACE, and PD-1 inhibitors versus TACE monotherapy as conversion therapy in patients with unresectable HCC; and second, through exploratory biomarker analysis, to identify a proliferating subset of CD8+ T cells whose dynamic changes in the peripheral blood may serve as a non-invasive biomarker for predicting therapeutic response.