Sandwich chain is a term used to describe a type of restaurant that specializes in sandwiches. Three popular sandwich chains are Panera, Arby's, and Cosi. Panera is a bakery-cafe chain with over 2, 000 locations in the United States and Canada. Arby's is a fast-food chain with over 3, 400 locations in the United States and Canada. Cosi is a fast-casual chain with over 100 locations in the United States.