As well, the CEO and other executives were unknowingly filmed and recorded whilst boasting about how they got Trump elected and said used "unattributable and untrackable" advertising to support election clients.
As the linked article notes, Cambridge Analytica "was secretly filmed discussing coordination between Trump’s campaign and outside groups -- an activity which is potentially illegal."
Not long afterwards, Mother Jones published a file photograph (link here) of that same Cambridge CEO with Alexander Yakovenko, Russia's ambassador to Britain. Russian ambassadors in NATO nations have a long history of working with and being directed by the FSB, Russia's Federal Counterintelligence Service, the spy agency formerly known as the KGB.
The picture was taken only days after Democratic National Committee files and emails hacked by Russian intelligence were dumped online just as the Democratic convention began. The previous month, the Trump campaign signed a contract with Cambridge Analytica for election assistance.
Because of this mushrooming scandal, Cambridge Analytica has suspended the CEO. The White House, for its part, issued its typically absurd "witch hunt" blather.
In spy lingo, an intermediary between two principals who never meet is called a cutout. Vladimir communicates with the cutout. The cutout then communicates with Donald. No direct connection between Vladimir and Putin can ever be found. The cutout uses a fake identity and disappears into the untraceable ether.
Trump has repeatedly wailed that there was no collusion and no contact with the Russians. If a cutout was used, that claim is technically correct but factually fraudulent.
And leading or taking part in a massive conspiracy like this is a felony to hide connections to associates.
Whilst Congressional Republicans will be busy looking the other way, you can be certain Robert Mueller will not be as he and his associates continue their criminal investigation into Trump and his circle. If Mueller didn't already know about this, he does now.