Maybe a war over Taiwan, or
other east-asian nations...
But heck, within 50 years i'll bet China will be able to project it's military power quite easily anywhere in the world. Bizzaro-trade wars or something by then.
I'd presume EU would still be allied (more or less...) with the US. Japan and South Korea.... who knows, but probably allies.
China.... other than North Korea, I have no clue. China could make lots of friends in 50 years....
Things are gonna be tense and akward in the future, though