The percentage of CD8+ T cells expressing PD-1 as a prominent activation and exhaustion marker was significantly (P <.0001) upregulated in 1G4 SIL, reaching levels comparable to melanoma patient TIL (Fig. 5A, Supplementary Fig. S9B), as corroborated by an analysis of median intensity (Fig 5B, D, Supplementary Fig. S9B). This evidence concerns the gene CD8A and melanoma.