So I’m in Teir 2 and my friend is in Teir 1 can we party with each other and play the infinity Challenge slayer playlist will it count if were playing against teir 1 and 2 players? 
explain?
Matchmaking has no way to tell which tier you made it into when you enter the playlist. You guys will be able to play together, but when you earn points, it will be against other tier 2 players, for him, other tier 1s.