PDCD1 and familial pancreatic carcinoma: In an obese mouse model of pancreatic cancer, depletion of tumor-derived C-X-C motif chemokine ligand 5 (CXCL5) enhances the efficacy of anti-programmed cell death protein 1 (PD-1) immunotherapy, which is mediated by the upregulation of CD8+ T cell tumor infiltration [68].