In the trailer, Mario appears to have something close to a Brooklyn accent. This is obviously a major departure from the squeaky Italian accent that he has in the video games, but it is somewhat similar to the accent that Bob Hoskins used in the 1993 Super Mario Bros. The Brooklyn accent is obviously derived in part from Italians who settled in that borough, which led many to wonder if Chris Pratt was actually Italian.
In fact, the actor is not Italian at all. He doesn't seem to have any notable Italian heritage in his lineage. That shouldn't necessarily matter, though. Mario was created by a Japanese corporation and his voice does lean a bit into stereotypes about Italian people. Still, it's undeniably jarring to see the character have such a different voice from the one that most people associate with him.