Importing an Import Mbox to Outlook involves the use of third-party software. The Mbox file is a type of file format used to store email messages and other data. It is not directly compatible with Outlook, so the use of a third-party converter is necessary. The converter will convert the Mbox file into a format that is readable by Outlook.
https://www.syscurve.com/blog/how-to-import-mbox-into-outlook.html