Across all treatment regimens, IFN-γ<sup>+</sup> cytotoxic lymphocytes frequencies were associated with treatment response and showed good discrimination, whereas circulating serum IFN-γ levels were not informative.<h4>Conclusion</h4>These findings support peripheral IFN-γ<sup>+</sup> cytotoxic lymphocytes as a candidate noninvasive biomarker for stratifying HCC patients receiving PD-1/PD-L1-based therapy. This evidence concerns the gene PDCD1 and hepatocellular carcinoma.