If you're interested in obtaining the Mass Transit DLC for Cities: Skylines, here are a few legitimate methods:
was released by Colossal Order as a follow-up patch to the massive Mass Transit DLC. While the DLC introduced blimps, monorails, cable cars, and ferries, the 1.7.2-f1 update was a free patch that fixed critical bugs and added quality-of-life features. If you're interested in obtaining the Mass Transit
If you have an .iso file, right-click it and select "Mount" (Windows 10/11) or extract it again. If you're interested in obtaining the Mass Transit
If you proceed to download the CODEX version despite the risks: If you're interested in obtaining the Mass Transit