To briefly summarize the existing evidence, known predictors for developing ICI-DM are mostly clinical and easy to identify, and include personal or family history of autoimmune diseases (either endocrine or otherwise), younger age, higher BMI, male gender, poor ECOG performance status, and anti-PD-1/PD-L1 or combined anti-CTLA-4/PD-1 therapy. This evidence concerns the gene CTLA4 and diabetes mellitus.