In the pancreas of newly diagnosed people with type 1 diabetes, few islets show peri-insulitis, and in these lymphocytic lesions, a large proportion is tissue-resident memory (TRM) cells, accounting for approximately 40% of the total number of CD8+T cells per inflamed islet—a proportion similar to what is seen in skin lesions of psoriasis.29 Here, CD8A is linked to type 1 diabetes mellitus.