Context: Marvel earned a great deal of money and recognition during the comic book boom of the early 1990s, launching the successful 2099 line of comics set in the future (Spider-Man 2099, etc.) and the creatively daring though commercially unsuccessful Razorline imprint of superhero comics created by novelist and filmmaker Clive Barker. In 1990, Marvel began selling Marvel Universe Cards with trading card maker SkyBox International. These were collectible trading cards that featured the characters and events of the Marvel Universe. The 1990s saw the rise of variant covers, cover enhancements, swimsuit issues, and company-wide crossovers that affected the overall continuity of the fictional Marvel Universe

Question: What 1990s comic line featured futuristic, sci-fi stories?
Answer: 2099 line

Question: What was the name of the specialty comics line created by Clive Barker for Marvel?
Answer: Razorline

Question: In what year did Marvel introduce trading cards based on their characters?
Answer: 1990

Question: What trading card company did Marvel team up with to license these trading cards?
Answer: SkyBox International

Question: What was affected by the increasing use at Marvel of crossover stories between comic characters?
Answer: overall continuity of the fictional Marvel Universe

Question: What series was set in the past?
Answer: Unanswerable

Question: What commercially successful comic did Clive Barker create?
Answer: Unanswerable

Question: When was SkyBox International launched?
Answer: Unanswerable

Question: What marvel character was featured on the first collectible trading card?
Answer: Unanswerable

Question: When did comic book sales begin to decline?
Answer: Unanswerable