Bing seems to be testing showing the number of people who visited a website listed in a search ad. The ad in the Bing Search results says X "visitors in the past month."
Here is a screenshot that Khushal Bherwani posted on X of this feature:
Google has shown in search results if you visited a website before, even in sitelinks. Heck, Google even had a way to filter by sites you have not visited yet.
But this seems different, this is specific to Microsoft Advertising's Bing search ads.
Forum discussion at X.
Update: Frank Sandtmann sent me an alternative version of this: