1. Build the legend in ArcMap.2. Ensure the same symbology is in the ArcGIS Pro map frame.3. Screenshot the legend in ArcMap using Print Screen or Snipping Tool.4. Save screenshot to a folder for the project.5. In ArcGIS Pro, Insert > Picture.This workaround is not ideal, however as any changes to symbology, etc., are no longer reflect in this as it is simply an image and not dynamic.