CD8A and melanoma: A pivotal genome-wide mRNA expression profile by Baitsch et al. of tumor-specific CD8+ T cells isolated from lymph node metastases (TILN) of vaccinated melanoma patients [4] showed that a gene set corresponding to exhausted CD8+ T cells [5] was enriched in TILN compared to functional counterparts [Gene set enrichment analysis (GSEA) [7,8]] (Figure 1).