You don't need a subscription to listen to podcasts on YouTube Music in the background, while casting or when offline without an internet connection.
Google has launched podcasts in YouTube Music for listeners in the United States
Google Podcasts
The first update to Google Podcasts for iOS brings CarPlay support
Google's new Podcasts app has made its way into the App Store on March 25, and just yesterday the iPhone and iPad software received its first update since launch.
The Google Podcasts app has made its way to the App Store
Google's official Podcasts app has launched on the App Store for the first time.