From April, the games from the Bethesda launcher will be playable (again) on steam. The publisher is closing their digital store.
This has of course to do with the acquisition of Microsoft and if you want to know exactly how this works, we recommend that you the FAQ from Bethesda. The migration will not be completed before May, so you still have plenty of time to transfer your games. The company does recommend that you do this as soon as possible.