Following this week's workshop on potential sites for the 2020 rover landing, the list has narrowed to eight candidates. The journal Science has a nice article summarizing the outcome. If you'd like to peruse the presentations from the workshop, they are available here. Jezero Crater won the vote among scientists at the workshop, but there are plenty of other favorites that have returned from the list of candidates considered for the Curiosity rover and in consideration for the 2018 ExoMars rover: NE Syrtis, Eberwalde, SW Melas, Nili Fossae Trough, and Mawrth. The biggest surprise for me was that the second most popular site was to return to the Columbia Hills explored by the Spirit rover to further examine its hydrothermal vents.
These eight semi-finalist sites will be further studied leading to a workshop in 2017 where the list will be narrowed to four and eventually to the one site where the rover will land and explore. The advocates for each of these sites now will work to put together the evidence to make their site the eventual selection.