A new Apple Support page has surfaced recently, telling users how they could add the Xbox Series X gamepad on Apple devices.
The page mentions that support for the Playstation DualShock 4, Xbox Adaptive Controller, Xbox Elite Wireless Controller Series 2 and the Xbox Wireless Controller with Bluetooth, among others have been added. The Xbox Series X gamepad will be coming as an update at a later time.

Adding a physical controller makes playing a more accurate experience. The gamepad can be used on supported games in the App Store or Apple Arcade. Furthermore, the controller can be used as a sort of remote on Apple TV.
The support page hasn’t mentioned support for the Amazon Luna gamepad or the PS5 DualSense controller. However, some individuals have reported seeing code that mentions the gamepads on iPadOS and iOS 14.3 betas.
Both Apple and Microsoft are working to make the Xbox Series X gamepad compatible in Apple devices.