Deadpool & Wolverine | Trailer 4

Even if the Deadpool 2 cameo messes up the timeline, it won't affect Deadpool & Wolverine much. Deadpool is being kidnapped by the TVA, an organization that exists outside of time and space. The TVA can drop him anywhere they want within the MCU, so it won't matter when they grab him within the Fox universe. In Loki, the TVA has the ability to travel to any point in time, whether it's the 1800s, medieval times, or 2056. Deadpool can easily join the MCU in the present day, regardless of where the TVA picks him up.

This also leads to a theory that Deadpool & Wolverine could be a journey through various points in the MCU timeline. One Deadpool & Wolverine synopsis stated that Ryan Reynolds' Deadpool and Hugh Jackman's Wolverine will embark on a journey that "will change the history of the MCU." That description suggests that the mutant duo will be traveling to iconic moments in the MCU and fixing certain things that will save the universe, but could affect other moments. Through the TVA's technology, Deadpool and Wolverine can travel to any moment they want.