CD8A and neoplasm: Immune active tumors that are sensitive to checkpoint inhibitors such as melanoma, lung squamous cell carcinoma, or lung adenocarcinoma are characterized by an abundance of CD8+ tumor-infiltrating lymphocytes (TILs), while pancreatic cancer (except those with defects in mismatch repair) represents an immune quiescent tumor characterized by lack of infiltration by effector T-cells that is otherwise critical in driving the antitumor response to checkpoint blockade [11].