Copyright Conundrum

Is there any copyright if we download a model for free from the asset store or buy one? Like, if I sell my game, must I give some profit to others?

Check the license that should accompany the model, or the policy on the site. I’m pretty sure Asset Store stuff is ‘use at will’ kinda thing, as long as you don’t resell it. Some models you get are free for ‘render only’ but not interactive 3D (such as games) and some are wide open.