Hilarie Burton said a few months back that she wouldn't mind making a few appearances. But when Sophia Bush was interviewed a month or so ago, she was asked if Chad and Hilarie would be returning for the last episode of season 8 (which is rumored to be the series finale). She answered that they were both contacted, Chad so no because he was too busy and Hilarie doesn't feel right coming back if Lucas wouldn't be with Peyton. So as of right now, I think not. But who knows? Miracles happen right?