Google and SiriusXM have partnered in order to enable streaming of the latter on smart speakers from the former. In addition, the content provider's subscribers will be able to activate and control their channels by asking the Assistant on their phones to do so. This update will start rolling out shortly in the US and Canada.
https://www.notebookcheck.net/The-Google-Assistant-will-start-integrating-SiriusXM-soon.440649.0.html