CentOS was created as open source distribution compatible with Red Hat Enterprise Linux (RHEL).
It was successful as it gave most of the benefits of RHEL without the expense.
RedHat acquired CentOS, saying that it would be good for CentOS[1].
RedHat shut CentOS down.
New alternatives are coming along to take the role of a free distribution compatible with RHEL.
[1]: https://www.redhat.com/en/about/press-releases/red-hat-and-c...