What does the Scrum Team do?

The Scrum Team is fully accountable for the activities necessary to the development of the product. These activities include collaboration with customers and other interested parties, verification, maintenance, operation, experimentation, research, and the development work itself, in addition to any other activities that may be needed (SCHWABER; SUTHERLAND, 2020).

In the Scrum Team, the Developers are accountable for conducting the end-to-end product development work, working in each Sprint on a value goal defined with the Product Owner based on the implementation of one or more Increments of the product.

The Product Owner, as part of the Scrum Team, is accountable for ensuring and maximizing the value of the product generated from the work performed by the Scrum Team members in order to satisfy the needs of the customers and users.

And the Scrum Master is accountable for promoting and supporting the understanding and use of Scrum, for facilitating and enhancing the work of the Scrum Team as a whole and for encouraging it to continually improve its processes and practices.

Scrum does not prohibit the same person from assuming more than one accountability, although I recommend avoiding this practice whenever possible. What I strongly advise against is for the same person to assume the accountabilities of Scrum Master and Product Owner on the same Scrum Team (see the section The Scrum Master is present in the chapter Scrum Master).