While Marvel Rivals is doing pretty damn well (shitty layoffs aside) with the whole lots of Marvel heroes coming together (not in that way) thing, there was once another way we could have seen the comics giant's costumed crew crossover - via an MCU-eque "Marvel Gaming Universe". For better or worse though, that idea never became a reality.
An MCU-esque "Marvel Gaming Universe" was once a thing we could have gotten, had Disney's execs decided it was worth putting cash into
Source: VG247 (opens in a new tab)