What's Up with Mueller?

Mueller has guilty pleas from two men who lied about not acting with the Russians: Flynn and Papadopoulos. Effectively they lied that they were not traitors and spies, conspiring with Russian officials. And, it seems that Russia would not act on the word of these underlings, but they would if they knew Trump was supporting these two conspirators. Why hasn't Mueller brought indictment against Trump and the rest already?