Kingdom Hearts 3 has been the only Kingdom Hearts game available on an Xbox console so far, but Square Enix has confirmed that the entire group of remastered collections will be available on Xbox One next year.
Speaking during X019, Kingdom Hearts 1.5 + 2.5 ReMix, as well as Kingdom Hearts 2.8: Final Chapter Prologue were confirmed for a 2020 release on Xbox One.
As of E3 2018, franchise director Tetsuya Nomura told IGN “we haven’t even started the conversation yet” with Microsoft about porting these collections to Xbox, though obviously things have changed since then.
Source: IGN.com Kingdom Hearts Collections Coming to Xbox One