In addition, a study revealed a significant correlation between tumor mutation burden (TMB) and clinical outcomes after PD-1 inhibitors, implying that tumors with high TMB would present a greater number of tumoral neoantigens and thereby would have a greater chance of being recognized by tumor-specific T cells [143]; however, since HCC proved to be less immunogenic compared to other tumors and showed a low TMB (approximately 5 Mut/Mb), the role of this biomarker in these patients remains limited [144]. The gene discussed is PDCD1; the disease is hepatocellular carcinoma.