This game does not allow to get any more soldiers than the predefined ones (drones not included). But you can get martian robot bodies after robots missions and repair them after researching the appropiate technology.
This mod uses the same trick: you can produce cloned bodies than can be "repaired", and then you can use them as any other of your soldiers. An annoying side effect of this technique is that the clones are "repaired" with only 1 HP like the martian drones, so they need a lot of healing before you can use them.
There are also a lot of other changes in this mod, with new items, technologies and trainings.
You can read more about the modification and provide feedback in this topic, or download it directly in our files section.