Because Grand Theft Auto: Chinatown Wars was originally a Nintendo DS exclusive title, it does not exist as a native, retail 3DS cartridge. Instead, players use custom QR codes to stream .cia or remote install files directly into their homebrew ecosystems via wireless remote installation. Why the 2021 Homebrew Boom Matters Today

Instead, the Nintendo 3DS plays the original via its built-in backwards compatibility. When you insert a GTA: Chinatown Wars DS cartridge into a 3DS, it works perfectly, but it runs in DS mode. You get the dual screens and touch controls, but no 3D effect.

You may be wondering why your search specifies "2021." Here is the historical context:

: The 3DS fully supports the game's original "tasteful" minigames, such as hotwiring cars, drug dealing, and searching through dumpsters.