Google has a feature that enables its AI to use data from your Gmail and other Google Workspace services to give you personalized search and more. It might be a nifty feature you'd like. But outside of the EU (protected by GDPR), they didn't ask your permission to run their AI on your personal data.
If you'd like to opt out, you have to take steps. I created a guide to help you disable Google from consuming your data with their AI:
https://www.podfeet.com/misc/gmail-opt-out-ai-training-A.pdf