

With the latest version of the app, rolling out on the App Store, Apple Watch users can say "Hey Siri, play music on Spotify" or any other voice command with "on Spotify" to control Spotify playback without opening the app directly.
Spotify gained Siri support on iPhones and iPads as of iOS 13 after Apple opened up its SiriKit framework to third-party music, podcasts, audiobooks, and radio apps.
Article Link: Spotify Now Supports Siri on Apple Watch