Rich Bowen has announced that CentOS 8 will be replaced by CentOS Stream by the end of next year.

CentOS Project shifts focus to CentOS Stream

The future of the CentOS Project is CentOS Stream, and over the next year we’ll be shifting focus from CentOS Linux, the rebuild of Red Hat Enterprise Linux (RHEL), to CentOS Stream, which tracks just ahead of a current RHEL release. CentOS Linux 8, as a rebuild of RHEL 8, will end at the end of 2021. CentOS Stream continues after that date, serving as the upstream (development) branch of Red Hat Enterprise Linux.
Meanwhile, we understand many of you are deeply invested in CentOS Linux 7, and we’ll continue to produce that version through the remainder of the RHEL 7 life cycle.
https://access.redhat.com/support/policy/updates/errata/#Life_Cycle_Dates
CentOS Stream will also be the centerpiece of a major shift in collaboration among the CentOS Special Interest Groups (SIGs). This ensures SIGs are developing and testing against what becomes the next version of RHEL. This also provides SIGs a clear single goal, rather than having to build and test for two releases. It gives the CentOS contributor community a great deal of influence in the future of RHEL. And it removes confusion around what “CentOS” means in the Linux distribution ecosystem.

When CentOS Linux 8 (the rebuild of RHEL8) ends, your best option will be to migrate to CentOS Stream 8, which is a small delta from CentOS Linux 8, and has regular updates like traditional CentOS Linux releases. If you are using CentOS Linux 8 in a production environment, and are concerned that CentOS Stream will not meet your needs, we encourage you to contact Red Hat about options.

We have an FAQ - https://centos.org/distro-faq/ - to help with your information and planning needs, as you figure out how this shift of project focus might affect you.

[See also: Red Hat's perspective on this.
https://www.redhat.com/en/blog/centos-stream-building-innovative-future-enterprise-linux