It appears that the REST API endpoint GET /task does not return the processDefinitionKey.
However the endpoint GET /history/task does return the processDefinitionKey.
Why isn’t the processDefinitionKey returned from GET /task? This is making things complicated for what I need to do.
It may not retrun the key, but it does return the definition Id. You could then make a call to lookup the key based on the id using this  API.
Thank you for your response. Yes, I understand I can make an additional call to get the key. It would obviously be more convenient to not have to make an additional call. Since the GET /history/task does return the key, I was just wondering if there is some reason that the GET /task can’t also return the key.? If it could do this, it might be a nice enhancement so that the two endpoints are more consistent (and thus more convenient for clients).