As a child I was diagnosed with rather severe ADD and the doctor suggested that I take up chess to help with concentration. He said that the desire to win would force me to have to concentrate.
Well, I’m not sure but I think it has helped. I still stink at chess because calculation is nigh impossible for me beyond a move or two. It’s also helped with memorization since I wanted to learn lines. But I still stink.
Chess is a skill that involves memory, pattern recognition, and calculation, and these are the kinds if things that are associated with intelligence. That said, it’s not a magic elixir; indeed there are lots of ways to exercise these skills.
There's probably a better link between chess strength and intelligence rather than soccer strength and intelligence, but the fascination with chess players=genius is flawed and unfounded in my mind.
Anyway, there are plenty of helpful forum topics.
History of chess: https://www.chess.com/forum/view/general/if-kasparov-never-existed-who-would-have-unseated-karpov-and-when
Specific Lines and refutations: https://www.chess.com/forum/view/general/good-line-against-dragon