748 Targeting vasoactive intestinal peptide receptor signaling in pancreatic ductal adenocarcinoma for enhanced anti-tumor response to checkpoint blockade by Yuan Liu, Susan Thomas, Mohammad Zaidi, Shuhua Wang, Haydn Kissick, Gregory Lesinski, Alan Frey, Sruthi Ravindranathan, Edmund Waller, Michael Ware, Bassel El-rayes, Rohan Dhamsania, Jingru Zhu, Anish Majumdar, Brian Robinson, Maria Cardenas, Tenzin Passang Fnu, Jian Ming Li, Sanjeev Gumber, Shanmuganathan Chandrakasan