On fox news. On his terms. Harris hasn't and probably won't agree to this. Trump will call Harris scared of debating him when she doesn't accept. Trump is unable to win anything in a fair fight (debate/election/criminal trial/etc)
Let's be real he won that debate against Biden and it rightly cost Biden his candidacy. The point isn't whether Trump can win fairly (or that he performed particularly well in that debate), the point is his entire life he has done everything to not have that be a necessity. Yet somehow this man is still the superior choice for tens of millions of people at the very least.