https://www.halowaypoint.com/en-us/community/blog-posts/enter-the-arena
After earning your starting rank, the ONLY way to increase your rank is by winning. For team-oriented playlists, this emphasizes the importance of team play. Whether you drop 30 kills in a game of Slayer or single-handedly capture every flag in a CTF match, wins are the only way to improve your CSR. As you win, you will progress through the 6 tiers of your rank. If you are skilled enough to continue winning at tier 6, you will advance to the next rank (yay!). Losing games will cause your progress within a rank to decrease, but you will never drop down a whole rank from losing. For example, if you spend all month working your way into Silver, losing wont drop you back to Bronze.
