Like there's one I found with "sumac" in it... I know of a sumac tree, but that's about it.
Sumac is a middle eastern herb/spice. You could find it in middle eastern stores if you want to try it. It's especially good on chicken. It doesnt come from the sumac tree we have here, I haven;t figured out why they have the same name LOL.
The simplest marinade I know for chicken is ground up onions, cardomom seeds, salt and pepper (you can omit the salt if you are on a low-sodium kick like I am). Marinade the chicken in it for as long as you like (overnight in the fridge is fine) then cook it as usual. This works on pieces of chicken as well as chunks on sticks for kebabs.
Simplest way to do tandoori or tikka is buy the spices from the local pakistani store and mix with yogurt and lemon juice, then marinade.
My favourite middle eastern style marinade is lemon juice, olive oil, herbs (oregano, thyme, basil, or italian herb mix... whatever takes your fancy), black pepper, salt (optional). This works on other meats too and if you marinade lamb chops in it for 2 days in the fridge you can cook them right on the BBQ.