Traditional can describe anything that follows tradition, or a usual way of doing things. Traditional Mexican food includes tortillas and beans. A bag of corn chips with chili and fake cheese sauce, on the other hand, is not traditional.
A tradition can be personal or national, and the adjective traditional has tons of uses. Traditional football might require a brown pigskin ball or a white soccer ball, depending on where you live. Your traditional national costume could be a sari, while your friend's is a kimono. And that walking taco? It's traditional carnival food for some.