Streaming games is not exactly new, but when the big boys start publicly investing in them, it can finally become real. While Google's Project Stream is set for the least resistance by requiring only a desktop Chrome browser, Microsoft Project xCloud offers a broad network with as many devices as possible. Based on SDC 2018 statements, this would include the Samsung series of Android-based Galaxy smartphones.
That's not exactly unexpected. When Microsoft tries to hit any device, it needs to include smartphones. And as far as smartphones are concerned, Samsung still has the (slowly shrinking) market share. So when Project xCloud targets the masses, Samsung claims that 2 billion gamers are probably Microsoft's best bet. Of course, this depends mainly on how many of these gamers own high-end Galaxy phones or, even better, Microsoft's minimum hardware requirements are support for streaming xCloud games. It probably should not be much, as Microsoft is trying to use its Azure cloud technology to do all the hard work on the cloud side while only transferring video and input between phone and server.
On this phone page, Microsoft says games would do this Work with either direct touchscreen or the connected Xbox controllers. This is not so difficult considering that xCloud is more like Xbox games than PC games. For now, Microsoft is pretty much silent about how controllers would connect to smartphones, but it's definitely an opportunity for Samsung to update and sell new versions of the Wireless GamePad controller.
VentureBeat notes that Microsoft is still shy if xCloud itself was available, let alone for Samsung Galaxy's owners. All are still in the preparatory phase, including Samsung, which releases new and updated game development tools for future mobile gaming experiences.