If you've ever been to Cancun, you can't help but notice that it is very touristy: the beaches are beautiful, they're lined with huge hotels and party people, and it's a fun place to crash for a weekend. It can be hard to find anything authentically Mexican in this place, but if you look, you can find some great dishes endemic to to the Cancun area. I like this article by KC Kudra that touches on this:
...tacos filled with pork skin in green sauce, beef, potato or Mexican sausage, cheese and potato quesadillas served with salsa or Tik-in-xic fish which is fish marinated in a sour orange juice and achiote marinade and baked in banana leaves. Tamales in Cancun are great and these are steamed cornmeal stuffed with pork, chicken, or beef.
You can read the full article here.