Since the release and quick exit of The Man From U.N.C.L.E., some significant things have happened.
Of course, the prospect of a sequel or sequels almost wholly depends on how well the film is received financially, and The Man From U.N.C.L.E. for all intents and purposes was a huge disappointment considering the level of talent involved.
The first movie ended with her hinted at becoming more important in the organization, so that shouldn’t be too hard to manage.
If an U.N.C.L.E. sequel happens, the filmmakers would certainly want to elevate Vikander to a lead role to maximize her potential (unless her new profile leads to scheduling conflicts).