I think foxes are only considered cunning because they have pointy noses. Other than that, I don’t see anything particularly sneaky about your average fox. They’re basically just dogs, except nobody feeds them, pets them, or takes them to the vet.
By that logic, dogs are obviously much smarter than foxes. I mean, how brilliant is it that you can simply take a dump and, moments later, a human shows up with a little plastic bag to clean it up for you? Now that’s an evolutionary advantage.
Which is why I’m fairly confident that doggos are the smartest animals on Earth.