There are CMSs that can expose the content via a simple API. Another important distinction between CMSs are those provide full templating system (Wordpress etc

There are CMSs that can expose the content via a simple API. Another important distinction between CMSs are those provide full templating system (Wordpress etc) and those that control the request, but don't put any restrictions on how the html is generated. You use standard .net/java/javascript to generate the template based on data from the CMS. Two completely different approaches.