How to find the most common group of players

I am trying to find the frequency or count of player compositions using SQL. Here is my dataset

event key                   team_id player_id
12235384031441051453625936  1       27
12235384031441051453625936  1       11
12235384031441051453625936  1       42
12235384031441051453625936  1       15
12235384031441051453625936  1       6
12235384031441051453625936  2       30
12235384031441051453625936  2       35
12235384031441051453625936  2       9
12235384031441051453625936  2       6
12235384031441051453625936  2       28

So for each event, there players on team 1 and team 2, the player_ids represent a player. I have roughly 500 events, and a lot of these players will appear in multiple events, but not always with the same players. and I am trying to find the most common team composition, for example, using the dataset above, I see players 27,11,42,15,6 in multiple events. However, I do not know how many times this composition appears.

I am trying to wrack my puny brain and I think partition by is something that is needed. I'm trying to put a "count" on each team composition to see how many times it appear, but I am struggling with putting together a coherent statement.