org-todo-state-tags-triggers

org-todo-state-tags-triggers is a variable defined in `org.el'.
Its value is

nil

Documentation:
Tag changes that should be triggered by TODO state changes.
This is a list. Each entry is

(state-change (tag . flag) .......)

State-change can be a string with a state, and empty string to indicate the
state that has no TODO keyword, or it can be one of the symbols `todo'
or `done', meaning any not-done or done state, respectively.

You can customize this variable.