We'll see. Off the top of my head, only Combine and SwiftUI are Swift only for now. And Combine has specific features that are explicitly meant to make it interop with ObjC (and @objc Swift) objects, e.g. KeyValueObservingPublisher. The other "hot new" Apple frameworks, like CoreML, ARKit, HealthKit, ResearchKit, etc. are all still written in and usable from Objective-C. They _are_ starting to use Swift(UI) in UIKit, but so far continue to wrap it in an Objective-C interface.