CD8A and neoplasm: Furthermore, compared to other tumors, pancreatic tumors are often characterized by a low level of activated cytotoxic CD8+ T-cells and an intense infiltration of immune-suppressive cells such as tumor-associated macrophages (TAMs), myeloid-derived suppressor cells (MDSCs), and regulatory CD4+ T-cells (Tregs) [85,89,90,91,92,93].