In a workflow of routing with resolve after executing the resolve attribute then it is having the ajax operation to be performed. During ajax operation some data need to be manipulated which will send request to the web server and after completing the service some information or data to be responded by the web server.
This resolve result when received in angular app will be injected in a controller. Once the controller is ready, then the normal workflow will be carried out i.e we are having binding to the scope ans so on.
You can also check out :General Routing workflow between several web pages