Common method/way to get processvariables irrespective of CMMN or BPMN

  1. I am looking for one common way/method to get the process variables irrespective of CMMN or BPMN. Is that possible?
  2. Whenever, I change something on Activity(process variable) (CMMN) its not available in the BPMN.

PS: I am passing back and forth the process variables to CMMN and BPMN by selecting all.