If you're serving the calendar file to a user, so that their Outlook install can receive it and add it I think serving an .ical file/response would work.
https://en.wikipedia.org/wiki/ICalendar
You could have a Laravel route return a response with the formatted data, and serve it with the text/calendar mime type.
@Snapey Yes 😅 I just meant maybe Laravel devs thought of this scenario and provided some easy to use tools (For example the easy to setup authentication)
@ligonsker A user will need to authorise access from your application to their Microsoft account. You’d then use an OAuth token to add events to that user’s calendar.