Because of its design, a Cherokee's unibody takes more abuse from flexing than a separate frame and body. That is why companies like T and J Performance have designed chassis stiffeners to run along the undercarriage. These stiffeners make the vehicles handle better and be more rigid. Here you can see the weld that fixed a crack (arrow) that occurred in the B-pillar of this XJ.
Though the vehicle's structural integrity is in the body, you can still do a little fender trimming to put on a larger tire and less lift. This owner hacked the fenders up to make more room. The wheel opening has been enlarged to a considerably bigger size than stock with Rusty's Off-Road fender flares to complete the look.