I routinely keep my appointments listed in my menu bar when working on my Mac. As someone who does a lot of block scheduling, this is just one more reminder of where I should be as I work through the day. I also use Bartender to thin down the menu bar so truly useful data, like this, can be visible.
There are a few ways to pull this off. Fantastical has a setting that lets me put the next appointment in my menu bar with the “Show Upcoming Item in Menu Bar” checkbox in the Appearance settings. Fantastical also gives you a calendar and list of events if you click on the menu bar icon.
There are also some apps to scratch this itch. MeetingBar is my favorite. It gives you plenty of control over exactly what will show up and also a nice scrolling list if you click on the menu bar item. Both MeetingBar and Fantastical work with the meeting services like Teams and Zoom so you can launch meetings from the menu bar. Also, MeetingBar has a cool flip board-inspired icon, and I dig flip boards.