In a popup blind!
I've hunted on the ground for several seasons now, and the key is to scout the area ahead of time to plan the placement of the blind.
You do the same with a treestand, but you are a little bit more restricted with your shooting lanes in a ground blind.
Unlike using a treestand, you can't see a deer coming from far away so placement is critical, and keeping the wind direction in mind is also.
Early morning hunts are bearable when the weather is hot, but evenings can be really bad if you aren't at least set up in the shade.
I do miss the 360 degree freedom from hunting from a tree stand, which I can no longer do due to physical reasons, but a ground blind you can't beat for comfort, and being able to move and stretch is wonderful, so they both have their pro's and con's.