A report evaluating pancreatic tissue from a patient with ICI-associated diabetes mellitus (ICI-DM), showed an enhanced peri-islet CD8+ T-cell infiltration and, in contrast to classic T1DM, complete depletion of insulin-positive cells, suggesting that ICI-DM may be correlated to a more rapid and severe necrosis/apoptosis of pancreatic beta cells than T1D [86]. The gene discussed is CD8A; the disease is type 1 diabetes mellitus.