Gum on a shoe can be stubborn, can't it? One effective way is to freeze the gum by placing the shoe in a plastic bag and leaving it in the freezer. Once frozen, try chipping it away with a blunt object. Another method is to apply a little bit of peanut butter, wait a few minutes, and then wipe it off. Have you tried any methods so far, or is this your first encounter with this sticky situation?