Call Screen is a feature that was introduced on the Pixel 3 back in 2018. It essentially allows Google Assistant to act as your literal real-world assistant, taking the call for you and asking questions on your behalf. Late last year, Google rolled out Automatic Call Screen to the Pixel 4, and now it's available on all Google Pixel devices.
As the name implies, Automatic Call Screen is the same great Call Screen feature, but it works automatically. Google will identify an unknown caller or a robocall and automatically screen the call before it rings your phone. If it turns out the call was not a robocall, your phone will ring a few moments later with some context about the call displayed on the screen. If a call is successfully screened automatically, you'll see a transcript in the Dialer app.
Google mentioned that this feature would eventually come to all Pixel devices. It started appearing on the Pixel 3 and Pixel 2 this week, and now Google has announced it will be coming to everyone. That includes the original Pixel and the Pixel 3a series. We don't know the exact rollout schedule, but as mentioned, it does appear to be arriving on devices now. Also, this is most likely still region-restricted to the US. You can find it in the Dialer app Settings under "Spam and Call Screen." Google has set up a nice step-by-step guide here for enabling Automatic Call Screen.