As presented in Figures 6B–G, our results showed that the expression of RRM2 was significantly positively correlated with all analyzed immune cells, including B cells (r = 0.48, p = 3.06e-21), CD8 + T cells (r = 0.336, p = 1.78e-10), CD4 + T cells (r = 0.257, p = 1.31e-06), macrophages (r = 0.394, p = 4.05e-14), neutrophils (r = 0.37, p = 1.19e-12) and dendritic cells (r = 0.456, p = 7.06e-19) in HCC. This evidence concerns the gene CD8A and hepatocellular carcinoma.