There are many user who want to sync their Gmail data with Outlook Account if you are one of them and your gmail not syncing with outlook then you can fix this issue by using following method:
Open Gmail
Go to setting > POP/IMAP tab > Enable IMAP
Click on Save Changes.
You can see more methods if you problem is not troubleshoot from this method. For Reference: https://emailspedia.com/gmail-is-not-syncing-with-outlook/