CIS generally refers to the Center for Internet Security, renowned for its Critical Security Controls (CSC) and CIS Benchmarks:
The current version of CIS CSC contains eighteen (18) primary controls that originated from the “SANS Top 20” that focused on controls to address the top twenty (20) critical security vulnerabilities that organizations face. The SANS Top 20 was transferred to CIS in 2015 and rebranded as the CSC.