The Leaderboard comes in three types:

  1. The overall ranking Leaderboard
  2. The 1x1 mode ranking Leaderboard (this also features hero filtering) 
  3. The 3x3 mode ranking Leaderboard

 The block on the left shows your current ranking of the selected type, and your position in the Leaderboard is indicated depending on this ranking.

 There is also a widget on the screen for the results from the last Season (this will be available after completing at least 1 Season)—it shows the top 3 players of the last Season depending on the selected type of ranking. Press the (i) button to see more information about the results of the previous Season.

The Leaderboard is always available to view, even if you don't participate in the Seasons with any hero/team.