We all already know, that Google safe all your search terms, that you ever had written, even if you used incognito mode. All websites and videos, even if you delete your search history and cookies.
But there is a one even more interesting thing, they listen to your microphone, and it really could that watch all your calls and translations using your webcam. One of the benefits of this, they can more accurately choose the advertising that they will show you. About other ways of using this data, we can only build theories.
But you will never find articles about that if you using Google Chrome. Because Google search engine shows you only web pages that Google wants to show you, Google company quite often trying to manipulate your mind, showing you only the part of the information, that they want.
Here are articles that explain the truth about google much better