Tuna salad is one of the most basic recipes of all time. Pop open a can of tuna, mix in a dollop of mayonnaise, add seasoning, and voila! And a tuna salad sandwich is almost impossible to screw up—unless, of course, you're Subway. In January of 2021, the sandwich giant got caught in a scandalous lawsuit surrounding its tuna subs. Apparently, Subway's tuna sandwich might not contain an ounce of tuna, or possibly even any type of fish.