It's an optional update, so you don't have to install it straight away. Microsoft has released the latest cumulative update preview for Windows 10.

Are cumulative update previews safe?

It is also the first cumulative update released for Windows 10 21H1, which was released last week. Unlike updates released on Patch Tuesday, the preview updates only contain bug fixes, performance improvements and do not include any security updates.

What does Cumulative update Preview mean?

Definition: A tested, cumulative set of new updates that are packaged together and distributed over Windows Update, WSUS, System Center Configuration Manager and Microsoft Update Catalog ahead of the release of the next Monthly Rollup for customers to proactively download, test and provide feedback.