Interestingly, a high level of immune checkpoint gene TIGIT is observed in this population (Fig. 7f), which is in line with previous conclusion drawn from the hepatocellular carcinoma (HCC) atlas investigation.30 MHC-II NK, a subset of the trNK cell population, exhibits a significant upregulation of genes associated with antigen presentation, including HLA-DRA, HLA-DQA1, HLA-DPB1, HLA-DQB1, and HLA-DR (Fig. 7c and Supplementary Fig. 11c). Here, HLA-DQA1 is linked to hepatocellular carcinoma.