On the other hand, scRNA-seq on CD45+-sorted cells from the immune checkpoint therapy (anti-PD-1 and/or anti-CTLA-4) of melanoma responders and non-responders revealed two distinct CD8+ T cell states associated with tumor progression or regression [28]: the first state contained upregulated levels of genes associated with memory, activation, and cell survival (e.g., IL7R, TCF7, and STAT4) and downregulated levels of co-inhibitory molecules, while the second state was enriched for genes associated with cell exhaustion (e.g., CD38, PDCD1, LAG3, CTLA4, and PTPN6). Here, PDCD1 is linked to melanoma.