That's right.  Both bands are doing it without the key voices that helped make these bands famous.  Styx without Dennis DeYoung is hardly Styx, but at least Tommy Shaw is there.  But Yes hiring a Jon Anderson sound alike should be criminal!  What do you think?

They each have new albums coming out and will be on tour together this summer.

If you're interested in this, information is on the Styx and Yes official websites.