Cambridge Analytica's sold their services literally as "election management agency" and promised to be able to influence a large number of undecided voters.

More than 87M people were profiled, and more than 3M people were targeted by Cambridge Analytica in 11 key states during the election to feed them the content that would swing their indecision towards Trump based on their psychological profile and preferences.

Trump paid for that, and Michigan and Pennsylvania and New Hampshire were all very close.

To boldly state that CA had no impact on US elections, Brexit and I don't remember which South American election when the people involved in it literally sold it and used previous results as evidence seems a bit of a stretch.

I might be wrong, but there's no clear way of knowing unless votes were not anonymous.