The Sony A7iii definitely has image stabilization built into the body to help with hand-held shots. Sony claims 5 stops (which is VERY good) for this camera's IBIS (in-body image stabilization). But, it works best for photos. It still works for video, but in-lens stabilization is a little more effective for video and viewfinder.
This helps me a lot because my lenses don't have image stabilization, and 50% of my photography is done hand-held.
Note that some Sony E-mount lenses do have image stabilization, referred to as OSS (optical steady shot). When using these, this camera optimizes the use of both in-body and in-lens systems.