This artist's concept summarizes our understanding of how the inside of Ceres could be structured, based on the data returned by the NASA's Dawn mission.
Using information about Ceres' gravity and topography, scientists found that Ceres is "differentiated," which means that it has compositionally distinct layers at different depths. The most internal layer, the "mantle" is dominated by hydrated rocks, like clays. The external layer, the 24.85-mile (40-kilometer) thick crust, is a mixture of ice, salts, and hydrated minerals. Between the two is a layer that may contain a little bit of liquid rich in salts, called brine. It extends down at least 62 miles (100 kilometers). The Dawn observations cannot "see" below about 62 miles (100 kilometers) in depth. Hence, it is not possible to tell if Ceres' deep interior contains more liquid or a core of dense material rich in metal.
https://photojournal.jpl.nasa.gov/catalog/PIA22660