CD8A and pancreatic intraductal papillary-mucinous neoplasm: Pancreatic immune TME evolves from a diverse T-cell mixture, comprising CD8+ T cells, T helper 1 (Th1, involved in cellular immunity), and Th2 (involved in humoral immunity) as major players combined with Th17 (which produce pro-inflammatory cytokine as IL-17) and Treg cells in low-grade IPMN, to a Treg dominated immunosuppressive state in human invasive PDAC [113].