AFAIK, the only way to move MIDI to/from Cubase (Mac) is via MIDI file. which is a royal pain.
The feature request: enable copy/paste of MIDI data to/from Cubase and other DAWs.
This should not be too difficult – usually it’s just a matter of understanding the clipboard formats on both apps. i.e., when I cut/copy MIDI events in Cubase, the SD3 plugin should understand that format (on the clipboard), such that the MIDI data can be pasted into SD3. And, of course, the other-way around: cut/copy MIDI in SD3 (e.g., MIDI notes from the Grid Editor, or Blocks in Track) should put this data on the clipboard in Cubase format (in addition to its own SD3 format, of course)