In a recent interview with IndieWire, Deadpool & Wolverine co-writers Rhett Reese and Paul Wernick revealed that Robert Downey Jr. was initially considered for a cameo in the film; he also read lines with Ryan. The scene was written and it had intended to feature Downey alongside Jon Favreau’s Happy Hogan before they knew about Doctor Doom’s casting, reuniting the duo in a playful nod to their work in the Marvel Cinematic Universe (MCU). According to the writers, Ryan Reynolds, who stars as Deadpool and is a driving force behind the franchise, personally pushed for Downey’s involvement.
However, the plans for this cameo were scrapped when it became clear that Downey was committed to a different role in the Marvel universe—that of Doctor Doom. Reese explained, “We would’ve loved to have Downey, but Marvel had this ace in their hole. He’s about to come back as this different character, and it just didn’t make sense to have him appear as Tony Stark.”
The writers had initially hoped to include both Downey and Favreau in the same scene, playing off their well-established on-screen chemistry. Despite Downey’s absence, Favreau’s appearance in the film still brought a familiar and beloved MCU connection to Deadpool & Wolverine.