Why OpenMp cannot be found when libomp has already been installed on Mac?

Following error info occurs when starting to build a c++ project on my Mac.

CMake Warning at cmake/check_requirements.cmake:64 (message):
  OpenMP not found
Call Stack (most recent call first):
  CMakeLists.txt:13 (include)


CMake Error at cmake/check_requirements.cmake:103 (message):
  can not find appropriate macosx SDK, find in
  /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk;/Library/Developer/CommandLineTools/SDKs/MacOSX12.3.sdk;/Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk;/Library/Developer/CommandLineTools/SDKs/MacOSX13.1.sdk;/Library/Developer/CommandLineTools/SDKs/MacOSX13.3.sdk;/Library/Developer/CommandLineTools/SDKs/MacOSX13.sdk,
  you may set SDKROOT manually
Call Stack (most recent call first):
  CMakeLists.txt:13 (include)

And I had already installed libomp and other tools.
Details about env is:

• Mac is mbp 2018 with intel core.
• cmake: version 3.26.4

I had searched a lot of answers, which all seems useless to my problem.
Thank you.