The Core Infrastructure Initiative (CII) has officially ended and been replaced by the Open Source Security Foundation (OpenSSF). Many CII activities have transitioned to the OpenSSF. For example, the CII Best Practices Badge project has continued by transitioning to the OpenSSF Best Practices Working Group, and you can continue to contact the badging project through its badges mailing list. The CII research conducted on open source software security by Harvard continues as part of the OpenSSF Securing Critical Projects Working Group.
The CII website and materials are still available so that they can be used, enable transition, and provide useful historical information.