This market will resolve at the end of 2050 based on available data and verifiable sources when the following conditions are set for a country:
A distinct region within the country must declare and gain its independence.
At least one other sovereign nation must officially recognize the independence of this region.
The declaration and recognition must occur before the end of 2050.
Market for 2030: https://manifold.markets/FlorinSays/which-countries-will-have-regions-d
Market for 2100: https://manifold.markets/FlorinSays/which-countries-will-have-regions-d-8684478bf61d
@JoshuaWilkes based on the market resolution rules Taiwan will not count, because it already fits the rules when this question was created.
Like it or not, Taiwan behaves as an independent country, the full recognition of independence is just geopolitics at this point. Or the opposite is also very possible, but not part of this market.