Rank Points are a new metric introduced with the launch of Ranked Seasons. After you complete 5 placement matches in the Ranked Seasons queue, your Rank Points as well as the number of Rank Points required to reach the next Division (e.g. Gold) and Tier (e.g. III) will be displayed on the Ranked tab. When you win or lose a Ranked Seasons match your Rank Points will increase or decrease, respectively. At the start of every Ranked Season, your Rank Points will be reset and you will need to complete 5 placement matches to establish your starting points for that Season.
ELO is used to track your skill in each matchmaking queue. This means that you have a unique ELO for Quick Match 1v1, Quick Match 2v2, Ranked 1v1, etc. We use ELO to find you the best possible skill match when you search for a game. We also use ELO to determine how many Rank Points you gain or lose. While Rank Points are reset with each new Season, your ELO in the Ranked 1v1 queue will persist and will play a role in determining your starting Rank after your 5 placement matches are completed in future Ranked Seasons.