Yoneda et al. conducted immunohistochemical analysis of the non-tumoral pancreas of a cancer patient with a history of pre-existing T2DM who developed irT1DM related to a combination of anti-CTLA-4 with anti–PD-1 mAbs administrated for renal carcinoma pancreatic metastasis. Here, CTLA4 is linked to type 2 diabetes mellitus.