Announced in October 2018, Microsoft's Project xCloud has always aimed to deliver Xbox games to you wherever you are. In fact, it's ready to launch on September 15 for Xbox Game Pass Ultimate subscribers, who will have access to over 100 games on day one. But that goal of having your games come to you isn't being delivered.
A more accurate statement is that they're coming to your Android device. Microsoft did introduce an xCloud preview for iOS back in February, but it expires today and the firm certainly doesn't seem to be doing anything with it.
Here's the issue. The iOS app had a fair number of restrictions, which have to do with Apple's App Store regulations. The most significant restriction is that you can only play one game on it, Halo: The Master Chief Collection. According to MacRumors, the guideline responsible for this is that "games offered in a game subscription must be owned or exclusively licensed by the developer." To be fair, there are certainly other Xbox Game Pass games that qualify for that.
The more major concern is that Apple doesn't allow for game streaming in the App Store. Both Google's Stadia and Nvidia's GeForce Now aren't available on iOS, and it looks like that's not going to change any time soon. Microsoft's TestFlight preview is ending today, and unless it updates the preview app, it will no longer be available.