A combo is a fixed, authored pairing of two Cubees from the same collection — every Cubee has at least one, and a few belong to two. With the right pair in Main+Duo, the combo effect activates.
The Combos menu holds 12 saved loadout slots so players can swap pairs without re-picking, and shows a slim card per Cubee (role, ability, combo) — full stats stay in the Cubees List.