"Mismatched pair" refers to two things or people that don't seem to fit or go well together because they are different or conflicting in some way. Full definition
Even if you're savvy enough not to send your credit card number, a predatory conference (has there ever been a more mismatched pair of words?) (sciencemag.org)
There's some great moments between mismatched pair The Rock and Kevin Hart, Jack Black stays on the right side of his persona, and Karen Gillan gets some great dance - fighting in. (decider.com)
Ivy and Bean are a plucky and seemingly mismatched pair, and through the telling of their imaginative and quirky adventures, Barrows manages to infuse humor that's palatable for both kids and grownups, and capture the mischievous yet ultimately well meaning spirit of elementary school students perfectly. (bostonmamas.com)