

The SS had many tasks. One of them was to protect the regime against coups from the army or SA.
At the beginning the SA also ran concentration camps, the SS took them over soon.
SS, Gestapo, and regular police were all under Himmler’s command via the Reichssicherheitshauptamt.
Gestapo was formed from preexisting secret political police forces.
Trumpism operates differently than Nazism. However Trump needs a loyal oppression infrastructure to build a more authoritarian system. ICE is on its way to enable that.
Not all guards of concentration camps or SS members were prosecuted. That was also an unusual situation as the Nazi state and the SS ceased to exist and was occupied for decades.
No ICE agent will be prosecuted for conducting arrests or executing warrants against illegal immigrants. Once mass torture, inhumane treatment, extralegal executions and such start, it becomes more risky for them.
We don’t know how bad it will get yet or what comes after. In the best case Trump and republicans lose the next elections. A New Democrat government could simply downsize ICE and only prosecute a handful of bad apples. Remember what happened after Abu Ghraib.