PDCD1 and familial pancreatic carcinoma: These characteristics are conducive to the large-scale expansion of this preparation for transfer to clinical applications with significant cost savings; SP cells also express PD1, and because of the design strategy including the PD-L1/PD1 negative signal inverter, PD-L1/PD1 immunosuppressive signals can be converted into activation signals, characterized by a strong killing capability against PD-L1 positive pancreatic cancer cells.