As the article What is CentOS explained all about CentOS, it is a distribution of Linux that is based on RHEL. Centos Stream was introduced with the discontinuation of CentOS8, which is now a distribution between RHEL and Fedora; at first, new features are considered for Fedora, and after they are sure of their stability, they are presented in the CentOS stream. It should be noted that the CentOS Stream distribution is a preview of RHEL, and eventually, new features will be released in RHEL.