Bethesda have already confirmed that The Elder Scrolls 6 exists, but they have also confirmed that the game is years away from release.
It means that, for the foreseeable future, The Elder Scrolls Online will be our only gateway into Tamriel.
Hines confirmed that the game is not being worked on at the moment- this indicates that no meaningful development on the title has begun yet.
Presuming that Bethesda begin development on the game next year (after assuming that they spend all of this year supporting Fallout 4 with DLC), then the earliest we can expect The Elder Scrolls 6 would be in 2019- possibly even as far as in 2020.