https://www.reuters.com/article/us-facebook-cambridge-analytica-leave-eu/what-are-the-links-between-cambridge-analytica-and-a-brexit-campaign-group-idUSKBN1GX2IO >British consultancy firm Cambridge Analytica lies at the center of a storm for using data obtained from millions of Facebook users without their permission after it was hired by Donald Trump for his 2016 U.S. presidential election campaign.