This is a default screen-mirroring functionally of many recent phones.
On my Huawei P20 pro I can start screen mirroring in "Desktop mode", to TV-Screen, where you can use the phone's screen as touch-pad, but an external keyboard and mouse are preferred in this mode.
From my quick test a few minutes ago, I'm able to:
- Launch game in full-screen or windowed mode.
- Move character using the standard WASD keys.
- Use skills using ZXCV.
- Click menu items and scroll using mouse pointer.
- NOT able to rotate the camera at all.
This could use functionality to use the mouse, example right-mouse plus mouse move.