There has been some reporting of this. The Trump campaign have been making huge digital media buys for a few months, ramping up significantly as of late, for obvious reasons. And a few data analysis watchdogs have said they have new data mining and analytics teams helping them to segment and target (at least one with ties to the now defunct Cambridge Analytica, and another most probably backed by Putin).
Here are a few articles regarding their recent plays and programmes — the MIT writeup about the Trump campaign app is especially interesting:
The Trump campaign is trying to make sure that Mr. Trump’s message will be almost impossible to miss even during the Democrats’ biggest week.
www.nytimes.com
Data analysis company Data Propria, led by a former Cambridge Analytica strategist, is reportedly working on President Donald Trump’s 2020 re-election campaign.
www.theverge.com
The fight for your phone is “where the game is going to be played.”
www.vox.com
Both presidential campaigns use apps to capture data, but Trump's asks to scoop up your identity, your location, and control of your phone's Bluetooth function.
www.technologyreview.com