The character creator describes picking your character's skin color as "difficulty" with white being the lowest difficulty and black being the highest. While this obviously seems like satire which criticizes race privilege in the US society, I wondered if it actually has a mechanical effect on the game.
No the game difficulty does not change according to your skin color
The game’s difficulty slider changes the color of your skin, for instance. The lighter the complexion, the easier the game. The darker the complexion, the harder the game. If you want a greater challenge, you have to play as a black character.
“This doesn't affect combat,” Cartman tells you. “Just every other aspect of your whole life." The difficulty slider will affect how much money you earn and how you’re spoken to during the course of the game, according to Eurogamer.
This is however as it seems only initial hype or speculation among fans since in a later interview people at Ubisoft stated that :
We reached out to the game's publisher, Ubisoft, who had no official statement but confirmed that it's just a joke,” GamesRadar reported. “It doesn't affect combat difficulty or any other aspect of gameplay difficulty. The slider changes skin tone, but it's purely cosmetic.”