That'll never happen. Hillary supporters would never support Bernie. They're delusional and blame Sanders for her losing.
The overwhelming bulk of voters who picked Sanders in the primaries, including myself, voted for Clinton with little hesitation. Any democrat on that ticket was better than Trump, or Cruz, or Rubio. Full stop.
To this day, I still don't understand Sanders voters who couldn't do the same, because their actions suggest they found the prospect of a President Trump less objectionable than a President Clinton. That flies in the face of basically all of Sanders's personal politics and proposed policies. When I don't get everything I want, I'll accept the next best option. They chose not even to do that.
Correction: They chose not to do what you saw as the next best option. ---