Metro Exodus Kills 3rd Party Keys

A post on Steam announces that what are being called stolen keys for Metro Exodus are being deactivated (thanks PCGamesN). Here's what Deep Silver is saying about this:
We have been made aware of illegal stolen keys being sold by an unofficial key reseller.

These keys have been obtained illegally from the factory where physical key printing had taken place prior to the announcement of exclusivity with Epic Games, due to the criminal nature of these keys, all unlicensed keys have been deactivated and activation / download of Metro Exodus without the executable file is no longer possible. In addition, the software will be removed from the Steam library of any players using an unauthorised code. The keys being sold on this platform are stolen goods, and are therefore illegal.

If you have been affected we strongly recommend you contact the seller who sold you the unlicensed key and demand a refund.

The only supported key sellers for Metro Exodus were Humblebundle and the Razer store.

Metro Exodus will return to Steam after 14 February 2020.