Still on Windows 10? Here's what Microsoft Defender can and can't do for you

Defender will continue to provide security even for unsupported Windows 10 PCs. But Microsoft still wants you to move to Windows 11.
CNET

If You're Stuck on Windows 10, Don't Skip the Free Extended Security Updates Program

Microsoft no longer officially supports Windows 10, but you still have an option to get one year of free security updates.