The classical Stepanov theorem strengthens the Rademacher theorem by establishing almost-everywhere differentiability for pointwise Lipschitz functions into Euclidean spaces. In this seminar, I will discuss my recent extension of the Stepanov theorem to a broader setting: pointwise Lipschitz functions between general metric spaces with a generalized notion of differentiability that unifies traditional differentiability in Euclidean spaces with Almgren's framework for multiple valued functions. This seminar is part of the activities of the Excellence Department Project CUP B83C23001390001