What color tie and pocket square should I wear?

I have a friend's wedding this month, I like to dress nice. My suit is black, with light grey pinstripes, which means they pretty much accentuate any color. I'm wearing a grey shirt, in honor of May being Brain Cancer awareness month and my baby niece being a 1 yr survivor of her brain tumor. I'm hoping to find a nice french cuff shirt, what color of tie and pocket square should I go with? I initially think red, blue!? Help me haha