This code system http://hl7.org/fhir/care-plan-activity-status defines the following codes:

CodeDisplayDefinition
not-startedNot StartedActivity is planned but no action has yet been taken.
scheduledScheduledAppointment or other booking has occurred but activity has not yet begun.
in-progressIn ProgressActivity has been started but is not yet complete.
on-holdOn HoldActivity was started but has temporarily ceased with an expectation of resumption at a future time.
completedCompletedThe activities have been completed (more or less) as planned.
cancelledCancelledThe activities have been ended prior to completion (perhaps even before they were started).
unknownUnknownThe authoring system doesn't know the current state of the activity.