CD8A and metastatic neoplasm: Treg cells were more numerous in cSCC (19.8% ± 8.6%) compared to normal skin (7.3% ± 4.1%), were markedly enriched in invasive or metastatic tumors (49.3% ± 13.8% in cSCC that metastasized compared to 23.5% ± 11.0% in cSCC that did not metastasize) and correlated with reduced CD8+ infiltration and function (median suppression 41.7%) and poorer differentiation [30,33,42].