You now have another major alternative to the built-in Mail app on your Mac. Microsoft has made Outlook for Mac free to use. You previously needed either a Microsoft 365 subscription or an Office purchase to use the email client. It's available now through the Mac App Store.
Microsoft unsurprisingly pitches this as a good complement to Outlook for iOS. You can hand off an email draft to your iPhone if you haven't finished writing it on your Mac, for instance. An upcoming Profiles feature will tie into macOS' Focus modes to help you limit notifications when you're concentrating on work. As with all Outlook versions, you can use email accounts from various third-party services, including Gmail, iCloud and Yahoo (Engadget's parent company).
The company isn't shy about some of the reasoning behind the move. The team is "rebuilding" Outlook for Mac with performance, reliability and accessibility in mind. The free download might spur adoption by users who'd otherwise never give it a try. And of course, this might spur adoption of Microsoft 365 and Office for customers who want tight integration between their email software and productivity apps.
The addition might be welcome. There aren't many big email clients for the Mac, with Mozilla's Thunderbird being the most notable. Some are either paid-only or unlock features with subscriptions. Even if Outlook doesn't always match their features, you now have an easy way to try it.