Select "Calendar" in the left side panel.

Select the account you would like to add a calendar from.

Enter the name or email of the person whose calendar you would like to add.

You will see your team member's calendar next to yours.

Tip! If you would like to remove a calendar, here are the steps.

Select the three dots next to the team member's name and click "Remove"

Microsoft Outlook is an email application. In addition to email client services, Outlook includes features for managing calendars, tasks, contacts, and notes, helping users stay organized and productive. Learn how to manage your account, set up your Outlook email signature, specify out of office hours, and much more.

How to Add/Remove a Co-worker's Calendar to Your Calendar in New Outlook