First of all lets not mix ansible and CI/CD. Even they both for automating things . Purpose is way too different.

For ansible it can do such

• Automate daily server(on-premise, cloud) configuration related tasks. Like user add, remove, firewall, webserver, start services on multiple server, file add to multiple servers etc.

For CI/CD it can do such

• It is basically set of instructions how,where & when codes are deployed to the servers. By servers mean which environment( staging, testing, pre-production or production) takes effect on code change.

Its missing lot of topics about these two but i hope i gave you brief difference about those two.