So Kosovo hasn’t officially been recognized by anyone yet.
But lots of countries are lining up to refuse to recognize it:
Azerbaijan
Vietnam
China
Spain
Russia
Serbia (obviously)
Also:
Cyprus, Greece, Slovakia, Bulgaria and Romania have indicated they will not recognize.
Last I checked Cyprus, Greece, Slovakia, Bulgaria, Romania and Spain are all EU states. Seems like Brussels will have a problem if some people don’t want to play along.