Ladder seasons

Ladder are a feature of StarCraft and StarCraft II, allowing for online matchmaking and a rotation pool of maps for each season.

StarCraft
A competitive ladder was added to StarCraft: Remastered in Patch 1.20.0. It added in a competitive ladder system, complete with rankings based off of the Fish server letter rankings.

StarCraft II
StarCraft II features a Versus mode, where players can battle similarly skilled opponents in order to rank up on a ladder. These place players into Leagues that are assigned after completing a number of placement matches.