A Facebook data theft of 1.2 billion users has just made the news.
https://cybernews.com/security/facebook-leak-exposes-users-hackers-claim
This type of data is primarily used for social engineering, and identity theft - fraudsters trying to get enough personal data to either hack accounts or convince other people they are you so they can steal your stuff!
Even if the claims are exaggerated it’s a good idea to change your Facebook password, enable two-factor authentication, and review your privacy settings. Also, keep an eye out for any suspicious emails or messages.
Tell your friends and family.
Stay safe!