Trump thinks that if he receives immunity while President or thereafter in a Earthly legal system, that he will not be held accountable for his actions or daisy chained effects thereof. Even if he received such immunity, he WILL BE HELD ACCOUNTABLE thereafter.
He will spend over 1000 years in Hell, face White Throne Judgement, and the Lake of Fire [alive or dead at time of being thrown into it]. He also has lead many people away from their faith and replaced God with himself in their lives and concepts. Money or prison will not get him out of the accountability problem he will eventually face. He is 78 going on 79 years and is a stressed man. If I were him, I would spend much more time worrying about this than his legal trickeries.
Also, I hope he is impeached and found guilty of such. He should leave the Presidency in disgrace.