It's a shame that Marvel fans were unable to see Tom Cruise as Iron Man in the MCU. Scheduling conflicts meant that the opportunity was lost, and when Doctor Strange 2 came out, they were disappointed to find that Tom Cruise hadn't taken on the role. Although he had been considered for the Iron Man trilogy, he changed his mind before giving it a real chance. That doesn't mean that Tom Cruise won't appear in one of Marvel's upcoming movies.
During an interview with Rolling Stone, Doctor Strange 2 writer Michael Waldron addressed the rumors of Tom Cruise playing Iron Man. The list of actors who almost played Marvel characters is full of famous faces (and voices), and Tom Cruise is at the top. Before the premiere of Doctor Strange in the Multiverse of Madness, there were rumors about cameos, including Tom Cruise as Iron Man.