A deal between Pokemon and Disney was recently reached, giving Disney-branded television both broadcasting and streaming rights. This deal will allow Disney to start broadcasting Pokemon on DisneyXD and allow it to stream on their Disney+ service. This deal only impacts people in the US.
Specific details behind the deal are also not known, such as what series and seasons Disney will be broadcasting/streaming and whether the catalog will appear all at once or in batches. Once that information is known, I will update this story!
Lately, Netflix has reserved the rights within the US markets to stream the new Pokemon show, which is currently Pokemon Horizons. Older episodes are also available. However, Pokemon's official YouTube channel has also been posting episodes - starting from the first episode - everyday, progressing through the seasons and series. It is also not known whether the deal with Disney will impact this. If I was to assume, it probably won't.
We don't know specific details behind the deal - just that it Disney would be premiering the show through their channel and streaming service within a couple months.
I am certain this will give Disney the exclusive rights to the next Pokemon series. Guess we shall see.