Unbeknownst to everyone who read *Secret Wars*, Deadpool was a major character in that story! That's the premise of *Deadpool's Secret Secret Wars* from 2015.
However, Deadpool visited St. Louis during another crossover (and in the backup issue of this book) – *The Contest of Champions*.
In "Rumble in East St. Louis!", Deadpool (Wade Wilson) is annoyed that the top-tier heroes get to fight while the B-Listers don't. To increase their popularity, he persuades The Grandmaster and Death to give them a shot at a battle. They send Deadpool, Doop, Frog-Man, Howard the Duck, the Pink Sphinx (making her first appearance), Rocket Racer, She-Man-Thing, and the Vile Tapeworm (also appearing for the first time) to East St. Louis. The goal is to find "the prize" before the other team does.
This story was written by St. Louis resident (at the time) Cullen Bunn and interestingly enough includes characters created by another St. Louis creator, Steve Gerber, such as Howard the Duck and Man-Thing (though in this case it's She-Man-Thing). This book has several notes that only a writer from St. Louis would know about – see if you can find them!