Microsoft and Apple are collaborating to allow for Apple devices to support the Xbox Series X controllers. This has been reported by a Reddit user who, in turn, has found the reference for the same in an Apple support page documentation.
This will make a whole lot of Apple devices such as the iPad, iPhone, iPod Touch, Apple TV or the Mac to be compatible with the Microsoft controller. There are no timelines mentioned though as to when the above is going to be made available. Instead, the only thing mentioned is that the above compatibility is going to be introduced in a future update.
However, there is no word yet if the PlayStation 5 DualSense Controller or the Amazon Luna Controller too are going to be integrated with Apple devices. At least, none of the above mentioned controllers finds mention in the Apple support pages though MacRumors is claiming both have been seen within the codes for the iOS and iPad OS 14.3 beta versions.
That likely points to the Sony and Amazon controllers made compatible with Apple devices sometime soon.