You can never go wrong with tracks, honestly. Walkers, since this is a fictional universe, may have their uses.
Tundras: Tracked vehicles, rated for cold weather operations, will be highly useful. Better traction than wheeled vehicles. Ground troops will want to clean the shit out of their weapons after firing them, then KEEP THEM DRY. That applies to crew served weapons as well. Aircraft will need very effective, well maintained anti-ice systems.
Sand Dunes: Still keep with tracks, though you'll be able to get more use out of wheels this time. Keep shit lubricated and filtered. Hydrate.
Grasslands: Really just about anything will go here. Tracks are nice, wheels are nice, shit, make walkers if you want.
Swamps/whatever?: Swamps are weird. They're gross as fuck. Keep your gear sealed. Tracks on some denser landmasses are okay. Wheels will get stuck, a lot. Hovercraft, maybe? Stick to flyovers in slow moving VTOLs as much as possible.