Pancreatic ductal adenocarcinoma (PDAC) is a fatal disease with a dismal response to single-use of immune checkpoint inhibitors (ICIs). ICIs combined with systemic therapy has shown efficacy and safety in various solid tumors. Nabpaclitaxel and gemcitabine (AG), as the standard first-line treatment for advanced PDAC, has been widely used in recent years. | Study protocol for an open-label singlearm phase Ib II study of combination of toripalimab nab-paclitaxel and gemcitabine as the first-line treatment for patients with unresectable pancreatic ductal adenocarcinoma