A very happy new year 2020.
Today i am going to share a tip on how to populate custom entity on the Unified Interface of Dynamics 365.
Suppose you have created a custom entity on web client of Dynamics 365 and published the entity and when you see on the web client it is showing the entity, but when opened the Unified Interface is not.
Resolution: open the Model driven App from the customizations area and add the custom entity over there and publish the entity app.
Dynamics 365 > Settings > Customizations > Model-Driven Apps
once you add the custom entity then save and publish.
Finally add the custom entity to the site map.
Now open the Sales Hub navigate to the section, there you can see the Sample Request entity.
I hope this helps.