Google announced at its I/O today that Google Assistant is arriving on iOS devices, as rumors suggested. The company is launching an app that should appear on the App Store soon. Sadly, Assistant will have limited functionality and will not work so flawlessly as it does on Android phones. Because of API restrictions, the Assistant will be able to do only basic stuff such as sending messages and playing music on Spotify, Google says. This means that when the screen is off, "OK Google" will not activate the device and have the Google app open. Also, Apple is not allowing remap of the Home...
Source: http://www.gsmarena.com/google_assistant_is_now_available_on_ios-news-25080.php