Man, people still clinging to the hope Robin will fight Trebol and even have a shot? Let's see some facts:
Trebol is ultra fast, is a logia, has super strength, a long and short range threat, and executive level. He was soo strong, Oda off panelled Usopp's whooping from Trebol, who didn't seem to have even broken a sweat. Robin already had a similar opponent in PH against Monet, who had no trouble stabbing Robin. Trebol is arguably much stronger than Monet. There's no logical way Robin has made the leap to this strong an opponent.