Microsoft Monetize - Audience analytics
You can use the Creative Frequency and Recency report to analyze your audience at a granular level and the Buyer Reach and Frequency Report to have an insight on how cross device impacted the number of times a single person saw the ads across all their devices.
With the Creative Frequency and Recency Report, you can view how often and how frequently users are viewing a specific advertiser's creatives.
With the Buyer Reach and Frequency Report, you can draw meaningful conclusions about the impact of cross device on conversion use cases.