Brad Sams of Thurrott writes that the two consoles, under the codename Scarlett, will be quite different. The first is a "traditional console" for those who like to play all of their games on their own hardware, though the specs are still unknown. The second device is a cloud-centric console designed specifically for streaming. It's reportedly a low-power device with just enough computing power for controller input, image processing, and collision detection, which should be enough to prevent latency. It will reportedly cost less than a traditional console.
“We do not comment on rumors or speculation," a Microsoft spokesperson told Tom's Hardware.
At The Verge, a report suggests that the streaming service is codenamed "XCloud." Microsoft is reportedly looking at combining Xbox consoles into server blades for data centers, which could be used for developers to create games and then later stream them directly to gamers.
All games will reportedly run on both Scarlett devices. The devices are rumored to launch in 2020, and the streaming service is expected to work on many devices, including PCs and smartphones.
Update, 11:45 AM ET: Added with a statement from a Microsoft spokesperson.