Another revamp of a classic is on the way with the Wolfenstein: Enemy Territory Single-Player project, which has announced a release on November 19, 2021.
What is it? Wolfenstein: Enemy Territory Single-Player is a free expansion for Return to Castle Wolfenstein - what could have been the single-player campaign of Wolfenstein: Enemy Territory. For the Linux version, they've confirmed it's going to work nicely with iortcw, the major open source enhancement project for RTCW. Release originally back on 29 May - 2003, the Wolfenstein: Enemy Territory Single-Player announcement was made to commemorate the 18th anniversary.
Their showcase is using RealRTCW, which is currently only officially supported on Windows by the main developer. However, that too can run on Linux and if you're on Arch Linux there's an AUR package for it. It seems the developer of RealRTCW is also interested in putting the Linux build up on Steam but they needed a little help - see more on Steam.