One way of comparing these two brilliant works is through the thematic comparison of how both texts present appearances vs. reality. This is something that is very much in evidence both in the magic of Prospero and the island and in the way that Volpone and Mosca trick and gull both the suitors and, towards the end of the play, each other.
In The Tempest, the massive role of magic in the play means that we as an audience are plunged into a new world where what we see happening is not necessarily what is really happening. We are like the characters who have been shipwrecked, as we are flung onto the island and are introduced to a new world where everything is mysterious and strange. Note what King Alonso says of the island and the magic he has experienced there in his final appearance in the play:
This is as strange a maze as e'er men trod;
And there is in this business more than nature
Was ever conduct of: some oracle
Must rectify our knowledge.
Appearances are infinitely deceiving, and the play is full of examples of the way in which characters come to erroneous conclusions because of appearances and how magic masks reality.
In the same way, in Volpone, it is the ability of Volpone and Mosca to disguise and trick others that leads to the presentation of this theme. We greatly enjoy the way in which these two rogues trick the suitors and make them believe in turn that they will be the person to inherit Volpone's wealth whilst at the same time no final assurance is given. However, as the play progresses, this is something that is deepened as we come to see that Mosca too is trying to deceive Volpone in precisely the same way.