If progress on a workstream is key to achieving one of your team's objectives, then use the workstream as the direct source of data for the objective's key results. When setting up the key result, choose the option to Measure Work to source a key result from a workstream and automatically measure work progress by calculating that workstream’s completion, its number of action items done or its average cycle time.
If the current status of a workstream is related to the success of a objective, align the workstream to the objective to display the relationship. Align the workstream from the the last page of the OKR wizard popup.
Anyone who views the objective can then see the completion, health, pace and status of the workstream and understand how it affects progress.