There are few components related to Workflow:

Users log in admin application with their credentials by identity provider ADFS. Once login is completed successfully, id token from ADFS is returned, which is used to access Data Access API and Camunda Rest API.
Data Access API accepts requests from admin application and stores user's data, does access control for security and business logic handling, and then forwards requests to Camunda for business process.
NiFi scheduler periodically picks up task data for process from Camunda database and transfer them to data access.
Data Access API and Camunda Rest API verify id token against public key of ADFS.
SSO is implemented in Admin application and Web application of Camunda. Once user logs in one application and then it is able to goes to another application without login again.