Google Assistant can now identify what songs are playing around you, in an update that just came out to all devices that have Google Assistant.
After invoking Google Assistant, you can ask “what song is this?” or “what song is playing?,” and the Assistant will pull up a card for you with the name of the song, the artist, lyrics, and YouTube, Google Play Music (of course), and Spotify streaming links.
The Pixel 2 and Pixel 2 XL have the ability to passively listen in to music around you and identify the song on the screen, but the song identification only starts working after about a minute of listening and only works on popular songs. Though that feature remains Pixel-only, the update adds the ability to identify songs on-demand for everyone with access to the Google Assistant.
Source: The Verge