Here is a keyboard case for your tablet with keys that function as a trackpad. The Mokibo Folio iPad Pro Keyboard Case holds your device at the right angle as you work. It has a touch sensor under the right half to distinguish between keyboard and mouse mode.
You can scroll using two fingers and perform 3-point gestures to interact with your iPad apps. The hidden trackpad area is up to 3 times larger than regular trackpads to give you more room to maneuver. You can pair the keyboard with up to 3 devices via Bluetooth and switch between them with function keys.