public sealed class CameraTrack : Track 

public List<CameraKeyframe> GetCameraKeyframes()
{
  var mapView = MapView.Active;
  if (mapView != null)
    return null;

  var animation = mapView.Map.Animation;
  var cameraTrack = animation.Tracks.OfType<CameraTrack>().First(); //There will always be only 1 CameraTrack in the animation.
  return cameraTrack.Keyframes.OfType<CameraKeyframe>().ToList();
}

public void CreateCameraKeyframe(TimeSpan atTime)
{
  var mapView = MapView.Active;
  if (mapView != null)
    return;

  var animation = mapView.Map.Animation;
  var cameraTrack = animation.Tracks.OfType<CameraTrack>().First(); //There will always be only 1 CameraTrack in the animation.
  cameraTrack.CreateKeyframe(mapView.Camera, atTime, ArcGIS.Core.CIM.AnimationTransition.FixedArc);
}