You want to change your setup to a content mashup (that is, an integration with SDL Tridion Docs), and you don't want to use the new Add-on service, then get your new resources from the following
• Content Delivery\roles\deployer\deployer-dx-combined\ for the combined Content Deployer upgrade
If you just want to perform a minimal upgrade, without changing anything, then get your new resources from
• Content Delivery\roles\deployer\deployer-sites-combined\ for the combined Content Deployer upgrade
If you want to set up the product to make use of the new Add-on service feature, then get your new resources from
• Content Delivery\roles\deployer\deployer-combined\ for the combined Content Deployer upgrade
Please refer to the link from SDL Documentation.
Please let us know if you are planning to upgrade or you going to perform fresh install and your requirements , so we can recommend accordingly