IDO1 and pancreatic ductal adenocarcinoma: Similarly, Yazdanifar et al. demonstrated that combining CAR-T with inhibitors of resistant factors such as indoleamine 2,3-dioxygenases-1 (IDO1), cyclooxygenase 1/2 (COX1/2), and galectin-9 (Gal-9) also significantly augmented CAR-T efficacy in the treatment of refractory pancreatic ductal adenocarcinoma [68].