Cambridge Analytica had no impact on Brexit and simply did bog standard online targeted advertising work, according to a report from the Informalities nation Commissioner.
"SCL/CA [Cambridge Analytica] were purchasing significant volumes of commercially available personal data in the main about millions of US voters, to combine it with the Facebook derived insight information they had obtained from an academic at Cambridge University, Dr Aleksandr Kogan, and elsewhere. In the main their models were also built from ‘off the shelf’ analytical tools and there was evidence that their own staff were concerned about some of the public statements the leadership of the company were making about their impact and influence."
"SCL/CA were not involved in the EU referendum campaign in the UK "
Far from being the all powerful maker of weapons grade propaganda tools (as Christopher Wylie might have you believe) , it seems that on the whole CA was using standard Facebook advertising approaches to do fairly standard targeted advertising. This is simply how Facebook and operate, rather than being some sinister international mind control conspiracy.