Google recently rolled out a new update for Chrome browser that added Picture-in-Picture mode to allow users to play videos while browsing the internet. While the public version of Chrome is running on v71, Google has already rolled out v73 to its Canary app.
In the new v73 update, Canary users now have an option to go back to the video easily using the button on the bottom right corner. This button is currently missing in the public version but might be added soon. To try the feature, you will need to play a video in PiP and then look for a button on the bottom right corner.
The feature is available in Canary builds right now and you can get it by downloading Google Canary but be advised that Canary builds are extremely unstable and not made to be used as the daily driver.