The Conquest Tracker is used to keep track of each side's progress when playing in Conquest Mode. Each side has a Conquest Tracker at the top of the World Map board.
World Map
The "World Map", also known as the "Global Operation Map", is a game board mainly used in Conquest Mode to keep track of which Regions someone has or hasn't taken control over, which also has the Conquest Tracker for both sides.
The World Map also contains the Alien Unit Tracker, which can be used in both Game Modes.