Windows 8 is out of support since 2016 as Microsoft explains and that includes Windows Updates:
Update to Windows 8.1 from Windows 8
Beginning in July 2019, the Windows 8 Store is officially closed. While you can no longer install or update applications from the Windows 8 Store, you can continue using those already installed. However, since Windows 8 has been out of support since January 2016*, we encourage you to update to Windows 8.1 for free.*