Moreover, this study highlighted that the absence of sNKG2DL in the pre-treatment serum of melanoma patients with improved OS correlated with the enrichment of few circulating T cell subsets (e.g., CD3+CD4+CD45RO+BTLA+, CD3+CD4+4-1BB+, and Th17) [21]. The gene discussed is BTLA; the disease is melanoma.