Harry Potter in MCU?

The Harry Potter series by J.K. Rowling is the best-selling book series of all-time. The main series of seven books starting with Harry Potter and the Philosopher's Stone and ending with Harry Potter and the Deathly Hallows has sold more than half a billion copies across the world. 

The book stars Harry Potter as he enters the magical wizarding world of Hogwarts and co-stars his close friends Hermione Granger and Ron Weasley. The books have been adapted into eight incredibly successful films and multiple spinoffs. At the height of their popularity, Harry and friends made a cameo in the Marvel Universe.

In New Excalibur #3 by Chris Claremont, Michael Ryan, Rick Ketcham, Tom Orzechowski, and Peter Pantazis, the superteam battles with evil versions of the original X-Men squad. 

The book opens with an out of costume Juggernaut running through London, accidentally smashing into buses and cars as he's trying to track down the evil X-Men. After getting told to run down an alleyway, Cain Marko nearly runs into a group of kids. There's little doubt the kids are supposed to be Harry, Ron, and Hermione.

Claremont and Ryan weren't exactly subtle about the cameo, as Hermione grabs Harry and yells his name as Juggernaut comes bulldozing down the ally. 

Ron asks, "what was that?!" as 

Harry responds, "dunno--but I'm glad it's not after us." 

There's little doubt the characters are from the world of Harry Potter: The kids are in London, they look exactly like their book/movie counterparts, and Hermione screamed Harry as Marko nearly ran into them. Does that mean that a version of Hogwarts exists within the pages of Marvel stories?

The cameo is a fun reference to the world of Harry Potter and marvel universe.