America can work because of squadron supreme of America and we know T'Challa has been tangling with nighthawk in Avengers, so there's an avenue there. I almost want to say I would like something like Russia or a place other that America to be where the issue arrives Because I don't want to only see Globetrotting take place in WK or the us lol. It's a big world out there and having it occur elsewhere gives an opportunity to create new and exciting villains and challenges for T'Challa (I especially want some new throwaway villain's for T'Challa to dispatch Some that have powerset that allows him to get a few more cool feats under his belt) while showing that WK intelligence spans the entire globe and outside of earth as well