https://www.cnet.com/news/pixel-pixel-2-google-lens-rollout-on-assistant/

Lens is a pretty cool AI feature that uses a heap of algorithms and Google's massive database to identify objects around you, and provide more information about them. Turn it on, point the camera at a landmark or thing, and Google Lens will try to tell you what it is. If you remember Google Goggles from 2009, Lens is like that, but all grown up.

The Pixel 2 and 2 XL phones both launched with Google Lens as part of the Photos app, which means you had to snap that open in order to trigger Lens. Now it's slowly rolling out within the Assistant app, according to some Redditors and tech blogs. This second location is convenient since Assistant is already associated with queries ("Will it rain at 8pm?").