Patients with HLA-DR3-DQ2 and HLA-DR4-DQ8 haplotypes have a higher chance of developing ICI-DM when treated with anti-PD-1 agents [46], although genetic susceptibility appears to be different in other ethnic groups, as another study [47] incriminated HLA-DR9 and HLA-DRB1*0405*03-DQB1*0401, while CTLA-4 and PD-1 gene polymorphisms also appear to play a role in the development of several autoimmune diseases, including type 1 diabetes mellitus [48,49]. This evidence concerns the gene HLA-DRB1 and diabetes mellitus.