Metro Exodus has had a considerably laborious launch, what with it being a long-awaited, fan-beloved, and critically-acclaimed game... all the way until the publisher announced that it was going to be released as a timed Epic Games Store exclusive. Then it all sort of fell apart.
Perhaps the most interesting thing in all this is the fact that Deep Silver waited a fair bit before announcing the game's timed exclusivity deal. As it turns out, the decision was made late enough that the physical game boxes required an Epic Games Store sticker to cover the reference to Steam.
Metro Exodus Epic Games Store sticker in question was applied very cheekily, with someone clearly hoping that buyers wouldn't notice that it was on top of the game box's protective layer. Obviously, it didn't take very long for people to notice what was rumoured to happen anyway.
In the end, if you got a boxed PC copy of Metro Exodus, you can just go ahead and scrape off the Epic Games Store sticker on the back (the one with system requirements and whatnot) to reveal the official Steam sticker that the game box was originally printed in mind with. Obviously, this was a matter of logistics, but good golly does it add a cherry on top of the whole mess.
For a thorough analysis of how Metro Exodus performs in its Epic Games Store iteration, we've got a bit of info on that, too, and as a bonus, read about the developers' worries on how the game was released.