Input in MRTK3 is mainly routed through two paths: Unity's input system and MRTK subsystems. Unity's input system is used for everything that it supports, from controller buttons and thumbsticks to controller/hand pointer poses. MRTK subsystems exist for other pieces of data that's needed for a broad set of interactions, like hand joints and speech. For more information visit https://aka.ms/mrtk3.input.package.