The Hulk’s visual isn’t as much about costumes as it is about colors. When he first appeared in 1962, he wasn’t the green goliath we know today. Originally, he was rendered in shades of grey. The creature’s creators shaded him as such so it couldn’t reflect any ethnicities, thus avoiding any exaggerated racial stereotypes. But the color was difficult to print in those days so the shades fluctuated between greenish-grey and blue. So, they changed his skin tone to green in the next issue, thus cementing the color he’s known for.
Since characters in comic books are generally printed in bright blues and reds when they’re the hero and dastardly greens and purples when they’re the villain, the Hulk’s coloring helped imply that he toed the line between each. Throughout his appearances in comic books, movies and television, some have argued that the morphed monster should be red with rage, not green. Regardless of this, the green has been embedded into his identity along with his short temper and simple speech.
And while Marvel had to stumble a bit when depicting The Hulk in cinema, he eventually become a very fleshed out, CGI masterpiece clothed in his iconic purple pants.