It is possible that the streamers you are watching are cheating. There are a number of ways to cheat in Warzone, including using wallhacks, aimbots, and other hacks. Wallhacks allow players to see through walls, while aimbots allow players to automatically aim at their targets. These hacks can give players a significant advantage over other players, and they can be very difficult to detect.
However, it is also possible that the streamers you are watching are not cheating. There are a number of legitimate reasons why a streamer might look to another screen when they push a team. For example, they might be checking their chat, looking at a map, or talking to their teammates.