CD8A and cancer: Cytotoxic CD8+ T cells, regulatory T cells (Tregs), myeloid-derived suppressor cells (MDSCs), mast cells, tumor-associated macrophages (TAMs), tumor-associated neutrophils (TANs), cancer stem cells (CSCs), and cancer-associated fibroblasts (CAFs) could account for PDAC progression and survival of PDAC patients7–14; however, the interactions among these factors in PDAC remain unclear.