Hey,
I get the cam_pose with respect to the world frame using this function:
zed.getPosition(cam_pose, REFERENCE_FRAME::WORLD);
And I get the current_pos, which is the position of an object with respect to world frame, using the object detection module of the ZED 2 camera:
zed.retrieveObjects(objects, detection_parameters_rt);
current_pos = objects[0].position;
I highly recommend you to visit the github page of stereolabs for more information. Look at the positional tracking and object detection examples.