https://techcrunch.com/2018/12/03/valve-changes-revenue-sharing-tiers-on-steam/

Valve announced new Steam rules over the weekend. It might sound like a small change but it’s the first time the company is changing revenue-sharing tiers.

Before the change, Valve would keep 30 percent of all revenue on Steam, including full games, DLCs, etc. Microsoft, Sony and Nintendo also take similar cuts on their own consoles.