"We're being sued for every case Mike Ross has ever touched" - it means their clients are now taking the law firm to court, presumably because they found out Mike is a fraud (this is not said in the video, but if you watched the previous seasons, you know what I mean). "Every case he has ever touched" means every case he was involved in (however small the involvement was).

I'm looking forward to season 6 myself - haven't seen it yet! :)

Anna, thank you so much) I haven't watched this show yet, but my job is to translate such small promos, so sometimes I am not aware of some plot details, so I need somebody to consult me :D

One more time , thank you!