10 Powers You Forgot MCU Characters Had
7. Hulk - Immortality
More an instance of forgetfulness on the part of the filmmakers than the fans, it is established very early on in 'Avengers Assemble' that the Hulk will not allow Bruce Banner to die and yet once the Big Guy is given a dose of stage fright by Thanos, Banner spends most of his time terrified of being hurt or killed by the various forces of evil.
It makes sense that Banner would operate the Hulkbuster to contribute to the battle in 'Infinity War' but it just doesn't add up that Banner wouldn't put himself in mortal danger to coerce the Hulk into emerging to save his own green skin.
It's clear that the Hulk isn't completely invincible given that using the Infinity Stones shrivels his arm up to near uselessness but the character is supposed to be nigh on indestructible. Every instance of Banner being put in danger of dying has seen the Hulk appear so there's no need for the character to fear death.
The MCU has been completely consistent in this from Ed Norton's turn as the Hulk right through to present barring this weird decision to completely ignore it for the sake of the plot.