Update to Google Maps allows Oreo's Picture-in-Picture feature to work on the app
The PiP in navigation mode will show the name of the road that you're currently on, or the turn that you are about to make, and an estimated time of arrival. This is the only mode that offers a PiP window that is useful on Google Maps, at least for now.
Also coming to Google Maps is a personal note feature that will allow you to jot down numbers and codes that you might need once you arrive at your destination. For example, if your friend lives in a gated community, you can type in the gate code so you won't have to hope that your brain can remember it. Restaurant fans will be able to add photos and reviews of their favorite dishes using a thumbs up rating system. Speaking of food, instead of opening the hamburger menu every time you want to find a feature, you'll be able to setup a shortcut inside the Maps UI.
Google Maps 9.60 is rolling out to Android now, reportedly through a server-side update. Watch for it.