Marvel wants Reynolds to become the most important character for the MCU. Therefore, a huge salary is expected for the actor.
After leaving the universe of its three greatest actors, Marvel is looking for people on whom to base their entire universe. It would seem that they already have enough stars, but for the studio it is not enough. Therefore, they are planning further moves that will significantly reduce the budget of any production where Deadpool appears.
According to information from scooper DanielaRPK, Marvel is preparing the largest deal in the history of the universe for Ryan Reynolds. The actor would become the best-paid person whose earnings would be even higher than Robert Downey Jr. This means that Deadpool will not only have more solo adventures, but will also appear in other Marvel films.