One way to achieve this is to use a multisuite tagging to send the data to a global report suite from the app as well as the web site. You would need to make sure you have stitching the visitors from app to going to website and vice versa.
With Adobe SDK implemented you can identify the visitor as a same visitor and ensure that visitors are not identified separately as they move from the native to mobile web. However this works one way only from App to Web.
For implementing the same, you can follow below help document links.