Doctrine is the set of beliefs that are taught by a group, be it a church or some other institution or gathering.Again, tell me how any of that is doctrine!
Because there are churches that teach and even have in their statements of faith some view of what they hold in both soteriology and eschatology, then such is doctrine.
Individuals may also hold as "doctrine" a specific set of views of soteriology. Theologians give titles to these doctrinal views of men: Calvinist, Arminian.
In the broad realm of the "Doctrines of Eschatology" there is great divisions between believers over the times and understanding. Often, these are "deal breakers" when it comes to associations and memberships.