Mostly drones and AI operated vehicles, I would expect. Lots of stealth styling and active camouflage.
As for the designs changing... tanks have evolved with advancements in technology. Yet, they are still tanks (tracked, armoured vehicles, carrying a gun).
I would imagine that tanks could be flatter if there were no crew, engines would get smaller, weapons would not need so much stowage area for rounds (especially rail-guns and laser weapons)... but tracks work nicely so I imagine they would still hang around... that and multiple wheeled vehicles. The K.I.S.S. designs with wheels and tracks would still be king... with anti-grav being more expensive and unreliable.
Don't forget walkers
!