Add this one to the list alongside the infinite stim glitch, the invisible player glitch, that one watch that made you visible through walls, and especially the bug that let a player bring their full loadout into the gulag. The latest Call of Duty: Warzone glitch lets you parachute into the gulag, and makes you invincible at the same time.
It's documented in the video above by YouTuber NTrippy, who judiciously doesn't show how he achieved this so other players can't copy the feat. Normally the gulag is where downed players get a fair fight for a chance to revive, but instead of waiting his turn in the arena NTrippy somehow parachutes from the waiting room into the arena two rounds early. When another player tries to shoot him he can't be hurt and proceeds to punch them to death while apologizing. "This is too dangerous," he says. "I gotta make sure the devs know about this so they can fix it."
It might be that this glitch is only possible in the current iteration of the gulag in Warzone season 4, which is inspired by the Hijacked map from Black Ops 2 and has replaced the Standoff gulag. Or maybe not. The only further information NTrippy gives in the video's description is to say, "No, executions don't work" and "It is a time-bound glitch, so once it's your turn in Gulag, the glitch is over."