As Mike says, there are more ‘proper’ wargames for MS platforms than Apple. Besides (I haven’t tried) I imagine the relatively small size of a tablet would be a bit limiting.
Anyway, two companies you may want to look at. Almost exclusively MS though.
Steel Panthers WWII and Steel Panthers MBT are free here, and are still being updated.
"I go online sometimes, but everyone's spelling is really bad. It's... depressing."