When I win a game does not make me rise in grade on slayer but when I lose a game it makes me go down grade.
Hey OP, the matchmaking feedback topic has covered this extensively. Any questions you have should be answered in either the first post or on the last few pages: https://www.halowaypoint.com/en-us/forums/58b8518e005f432381ab99fbcaf931e0/topics/matchmaking-feedback-update-%e2%80%93-june-11/f8c32226-26a6-4f1f-8899-ff162b0a5fae/posts