Call Screen is a feature, introduced at the launch event of the Pixel 3 lineup, and as promised, it now comes to the older generation of Pixel's with an update to the built-in Phone app in a beta form just for now, but it should hit the stable release soon enough. The version of the Phone app you should be looking for is v 26.0.222117411 from November 21, which also includes bug fixes and Visual Voicemail support for select TracFone users (in the US only).
- Introducing Call Screen for Pixel (US English only for now)
- Visual Voicemail support for select TracFone users
- Bug fixes and performance improvements
Call Screen enables the Google Assistant to answer calls for you, and in real time shows what the person on the other side says in a written format. It comes useful when you are in a meeting and you cannot take the call and talk, but you can still read what is going on. Keep in mind that it works in English US only.
Overall, this is a great update for people who still use the Pixel 1 and Pixel 2 series of phones, as this was already available for the 3-rd gen devices. If you happen to not be able to get this update from the Play Store, you can sideload it by downloading the corresponding APK for your phone's screen density and CPU architecture from the link below. These APKs can actually be installed on many Android One phones, and others too.
Call Screen seems to be only available in the US for now, and only for a limited amount of users. Did you try it already?