CTLA4 and pancreatic adenocarcinoma: Although traditional ICBs, such as anti-PD1, -PD-L1, and -CTLA4, have shown considerable clinical benefits in some patients with cancers, including non-small cell lung cancer, melanoma, and colorectal cancer [4], there is one major challenge in the lack of response of certain cancers such as pancreatic adenocarcinoma (PAAD).