XCOM: Chimera Squad Field Units are in no way associated with your agents or androids. These are the teams that you create on the city map and which bring certain bonuses once a week.
From the very beginning of the game, it is possible to create field units of the 1st level for each district in the city. Pay attention to the scale of discontent in the area. To it right, at the very end there is an empty square. Click on it and you will see a menu for creating and improving a field squad. There are three types of field units, and all of them can be upgraded to level three. Also here is a description of the bonuses that the unit provides at the first, second and third levels.
At first, you can only create units of the first level. Intelligence is spent on this – one of the three main game currencies. To unlock the second and third levels of field units, look for relevant research in the assembly complex.