To analyze the immunological response and tolerance to immunotherapy in HCC patients, we chose CD274, CTLA4, LAG3, HAVCR2, IDO1, and PDCD1 as immune checkpoint-related signatures and CD8A, CXCL10, GZMA, CXCL9, GZMB, GZMA, IFNG, PRF1, TBX2, and TNF as immunological activity-related signatures. This evidence concerns the gene IDO1 and hepatocellular carcinoma.