BusinessKey is missing in both runtime task query response(rest api) and history task query response(rest api) .
When i want to associate businesskey to the tasks, i have to make additional rest api call to get businesskey for the processinstance id of the tasks.
It causes huge performance impact for just querying for one businesskey.
If businesskey is added for task list response(GET, POST) rest api would be more efficient.
Created a jira ticket: https://app.camunda.com/jira/browse/CAM-10804