The game's publisher, Paradox Interactive, uses a proprietary launcher. If you purchase the game directly from the Paradox Store, they will email you a digital key. You must redeem this key directly inside your Steam or Epic Games client to add the game to your library. 3. Retail Copies
A shared text file on a public forum cannot generate a unique, unactivated server-side key. Safe and Affordable Ways to Play Cities: Skylines cities skylines license key.txt