With Windows 7 and Windows 8 support in Steam ending, it seems that Nintendo GameCube and Nintendo Wii are in. Yeah, it's a weird turn of events but also a case of strange timing. Today we've also got confirmation that the popular console emulator called Dolphin is officially coming to Steam.

Popular GameCube and Wii emulator Dolphin is coming to Steam.
There's no word on when exactly it will become available, but the Steam store page for Dolphin is live right now. The page cleverly doesn't showcase any Nintendo games or say the word "Nintendo," for that matter. Or GameCube or Wii.
"Dolphin Emulator is your one-way ticket to nostalgia if you're looking to relive classics from the big N's cube-shaped and motion-controlled consoles," writes the official description. "Return to an era of gaming before the advent of microtransactions and experience a diverse library of thousands of titles that were released for these consoles over a span of 15+ years. Dolphin Emulator allows these classic games to be reborn into the modern era with support for 4K displays, modern controllers, and much, much more. All of this fully Open Source and free to download."
And if you're wondering what sort of hardware you'll need to run these cube-shaped and motion-controlled games, that would be an NVIDIA GeForce GTX 760 or AMD Radeon R9 280.
As to how Dolphin will work on Steam, that's yet to be revealed. The developers have noted that a guide outlining the process and features will arrive once Dolphin is available to download. Emulation is a hot topic, that's for sure, and Nintendo is no stranger to taking swift action against sites and places that host ROMs (i.e., packages) of games for its consoles.
How this will play out on Steam remains to be seen, though it sounds like getting to this stage took "many months of work," so odds are it's already been approved. One thing is for sure. Once Dolphin goes live on Steam, its forums will probably become the most heavily moderated on the platform thanks to all the "where can I download.." threads.
From Metroid Prime to Super Mario Galaxy to The Legend of Zelda: The Wind Waker, the GameCube, and Wii have some absolute gems in their libraries. And getting to play any of these on the Steam Deck would be a lot of fun.