To understand the underlying molecular mechanisms, we constructed and compared the GRNs for PDhi CD8 T tumor infiltrating cells (i.e., CD8 T cells with a high expression of PD-1 in melanoma) and three corresponding T cell subsets (i.e., CD8 naïve, CD8 Effector memory, and CD8 Central Memory T cells) in the PBMC of healthy people. Here, CD8A is linked to melanoma.