Once your Marketo Connector is confirmed working. You're able to create Marketo Smart Lists to view AdRoll activity alongside your other Marketing campaigns. For more information on Smart Lists, this article is an introduction.
AdRoll + Marketing Campaigns Smart Lists
In the example below, we are searching for people that have had an AdRoll View-Through Conversion in the last 30 days, and also are in a specific Marketing Campaign:
AdRoll + Google Adwords Smart Lists
You can even combine multiple advertising vendors together, in this example we are looking for people who had an original referrer from Google ('gclid') and also clicked an AdRoll ad in the last 30 days: