PDCD1 and neoplasm: Currently, several strategies are employed to target the PC immune system: the use of monoclonal antibodies (mAbs) against the tumor antigens, targeting immune components [e.g., tumor-associated macrophages, tumor-associated neutrophils, pancreatic stellate cells (PSCs), tumor-infiltrating leukocytes, and cancer-associated fibroblasts (CAFs)], as well as blocking immune checkpoints, such as programmed cell death protein -1 (PD-1), programmed death-ligand 1 (PD-L1) and CD40 [6,7].