The atlcache.h file was a part of the ancient ATLServer that was released to the public many years ago by Microsoft which ceased maintaining it.
An internet search found a copy of that file at https://github.com/gabegundy/atlserver/blob/master/include/atlcache.h
You will need to determine if that copy (and any other old ATLServer files) can be successfully used with VS2019.
Also, see https://devblogs.microsoft.com/cppblog/atl-server-visual-c-shared-source-software/