We live in the Detroit area. My wife was raised in a section of town that is now referred to Mexican town. She had Mexican friends and attended school with them so Cinco de Mayo was celebrated. About 7 years ago we were staying at a resort in Playa de Carma during Cinco de Mayo and thought there would be a big celebration. We asked and all we got was a puzzled look. We explained to them about how big it was in Detroit. They said it must be a gringo thing and to them it is nothing special.
Maybe things have changed since everyone likes to capitalize on a chance to make more money but don't expect anything spectacular.
If you want to celebrate it stay home since most US bars are willing to clebrate anything to increase business.