Why is the pancreas considered part of the immune system

The pancreas is composed of exocrine and endocrine tissue. It is apart of the endocrine system as it secretes digestive enzymes

The pancreas is a glandular organ in the upper abdomen, but really it serves as two glands in one: a digestive exocrine gland and a hormone-producing endocrine gland. Functioning as an exocrine gland, the pancreas excretes enzymes to break down the proteins, lipids, carbohydrates, and nucleic acids in food.