The Nintendo Switch 2 has a new feature called GameShare, allowing an owner of one game to share it locally with up to three other Switch 2 and original Switch consoles. It also supports online play with other players,

Nintendo implements a new feature on the Switch 2, exciting fans who feel like it's the return of a nostalgic DS feature that many have been missing.

This appears to run similarly to the “Download Play” option for the Nintendo DS. For example, one person may own a copy of Big Brain Academy: Brain vs. Brain, but using the new GameShare option, your friends can jump in and join you to play, even if they don’t own it.