Revealing mistake: Just after Proxima Midnight and Corvus Glaive land in the train station, there is a wide shot where they begin approaching Wanda and Vision. In the wide shot, their shadows do not appear to match up with each other, despite being under the same lighting. Proxima Midnight's shadow is positioned in front of her and is quite heavy, but Corvus Glaive's shadow is positioned more to his left and is much lighter than Proxima's. (00:40:20)





Answer: Although many fans speculated it was because the Hulk fears Thanos after Thanos easily defeated him at the beginning of the film, the Russo brothers have since come out and said that it's because the Hulk feels that Banner only wants the Hulk around for helping him in fights, so his refusal to transform is a protest of sorts.
Phaneron ★
I think it's both.
Well it's not both. The Russo Brothers, who directed the film, have openly stated that the Hulk is not afraid of Thanos.
Phaneron ★