The artists involved with the upcoming X-Men: Blue #9 and Spider-Man #20 are changing, according to a notice sent out to retailers by Marvel Comics earlier this week.
Nico Leon is returning to Spider-Man for September 6's Spider-Man #20, replacing the originally-solicited Oscar Bazaldua. Leon had previously worked on the character before launching the Hulk title.
Meanwhile, Cory Smith will be joined by Thony Silas on August 9's X-Men: Blue #9. Silas is taking over DC's Blue Beetle in October, so this will presumably be done before that.