There is a known issue in the old installer that when GPU driver is installed, CPU RT cannot be installed. https://www.intel.com/content/www/us/en/developer/articles/technical/intel-cpu-runtime-for-opencl-applications-with-sycl-support.html describes this known issue. You can try the workaround provided in this link. Or you can update to the higher version, since this issue is fixed in 2021.1.
Additional, this is the release notes for Intel® CPU Runtime for OpenCL™ Applications (https://www.intel.com/content/www/us/en/developer/articles/release-notes/opencl-runtime-release-notes.html). You can find more details for the versions supported on Windows10.
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