There is no out of the box integration that makes Recommendations in email as easy to setup as a typical Target activity. But below is information about making a connection between Target Recs and any email service provider in general.
If the visitor accesses their email from a browser that has previously visited the website, their browsing behavior might be considered by Recommendations, but I am not sure about this, and need someone with a deeper technical understanding to confirm. The Last Viewed, or Trending algorithms will work as expected.
Here are three custom methods for accomplishing the integration:
Using method 1 or method 2 requires Campaign to make calls to an external API on a per-customer/per-email basis and wait for content to be returned. These methods are not supported by all ESPs. Contact your Campaign technical resource to determine if it is compatible with this integration pattern.
Using method 3 requires your email service provider to join together a list of recommendations by product ID or category ID to your list of emails. This method can be based on an attribute such as the customer’s last viewed product, last purchased product, or most viewed category. However, your email service provider must have access to this data in its customer profile in order to perform the join. Contact your Campaign technical resource to determine if it has access to this data and is compatible with this integration pattern.
You can find more details about implementing one of these methods within the documentation available here: https://experienceleague.adobe.com/docs/target/using/recommendations/recommendations-faq/integrating...