Cities: Skylines on X: "Paradox Interactive is participating in the Steam Winter Sale; get up to 10% off on Cities: Skylines II and 70% off on Cities: Skylines! Get your favorite game
Cities: Skylines on Steam
Cities: Skylines - Wikipedia
You can really create stunning skylines with just the base game in CS:2 : r/CitiesSkylines
Cities Skylines 2 base game lacks a key building feature, dev confirms