I don't understand the call to see tax returns. It's not like Trump helped write the Tax Code for all the 'Loopholes' I'm sure he's using. Plus, we've known he's been a Billionaire Real Estate Developer for 40+ years, so there's not going to be any surprises as to how he got rich. Nor is there a line for "Russian Contributions to my Presidential Campaign", on any form I'm aware of. Plus I can guarantee that his are so complex as to require a Tax Attorney just scratch the surface, as I'm sure there are things in it that go back to Tax Court rulings to understand.
However, I would to see not only the tax returns, but the brokerage and other statements of long term congresscritters who are now multimillionaires on a congresscritter's salary.