Microsoft is currently doesn't have any plans for a streaming-only Xbox console. Xbox chief Phil Spencer confirmed this in an interview with GameSpot.
"Last year we talked about xCloud and then we said we were working on new game consoles, but that's all I said." Spencer clarified, "We didn't say that [a streaming console was in the works]. I think maybe some people thought that that was the disc-less one that we just shipped. We are not working on a streaming-only console right now. We are looking at the phone in your pocket as the destination for you to stream, and the console that we have allows you to play the games locally."
"I think that the cloud inevitability as part of gaming is absolutely true," Spencer continues. "But we have more compute devices around us than we've ever had, whether it's your phone, a Surface Hub, or an Xbox. The world where compute devices are gone and it's all coming from the cloud just isn't the world that we live in today."
Microsoft is working on the successor to the Xbox One, codenamed Xbox Scarlett, which is planned for the end of 2020. xCloud, Microsoft's streaming service, will be getting its first bèta test this October.