According to a statement from Valve, Apple "revoked its approval" of Steam Link on May 10, one day after it was officially announced. The app had been initially been approved on May 7, but Apple suddenly rescinded its approval. The company cited "business conflicts" in its rejection and Valve's appeals have so far been unsuccessful.
The news comes as disappointment to many gamers and to Valve, which says it "spent many hours on this project and the approval process."
Full news source :- https://mashable.com/2018/05/25/steam-link-app-ios-rejected-by-apple/?utm_cid=hp-h-3#fk4zBsIk2qqg