Anything from 243win to 270wsm is ideal, some may say the .243 is small for mule deer.
so anything in the .25 to .27 calibers would be ideal IMO.
If I wanted an antelope specific cartridge it would be the .243win.
but for a antelope/mule deer I think I'd get a .270win or .270wsm, or maybe a .257wby if I had the itch...