This page tracks a proposal from the schema.org team for modeling various kinds of roles and contributions in a way that allows rich qualification. For example, when we say that a Person was an actor in a Movie, we might want to mention their characterName too. When we say that a SportsTeam has a Person as an athlete, we might want to mention the position that they play, or the time period in which they fulfilled that role.
To achieve this, a type "Role" is proposed, alongside a new property, "hasRole".
The full details are attached in a PDF document.