PDCD1 and pancreatic neoplasm: We analyzed a publicly available single cell transcriptome sequencing data from Genome Sequence Archive containing 24 pancreatic cancers and found that the intratumoral CD8+ T cells of diabetic patients (n = 14) had higher expression of immune checkpoints such as TIGIT, CTLA4, and PDCD1, but lower levels of IFNG and GZMA, than those of non-diabetic patients (n = 10) (Fig. 1B), suggesting that CD8+ T cells tended to exhibit an exhausted condition with impaired tumoricidal functions in the presence of high glucose.