Yankel, if by collaboration you mean joining the government, then no, the satmar rov holds that’s assur.
If you mean on an individual level, like a business partner, then it’s no different than a goy and you can.
If you’re referring to working with them to save jews during the Holocaust, then nobody every said that’s not allowed.
——————————-
Saving Jews in Europe is mutar .
Saving Jews in EY is assur ?
Ma nishtana ?