Biggest concern for Facebook has got to be them investigating the other sharing of data beyond Cambridge Analytica. I seriously doubt they turned the other way for conservative but not liberal think tanks / firms.
Palantir, in my guess, is probably like CA on steroids.
Looks like CA is just one means Palantir has used to get Facebook data.
https://www.nytimes.com/newsgraphics/2016/news-tips/index.ht...
The unique data is the friend graph and the likes, which they can use to (quite effectively) predict political attitudes.