Do you want to use Tableau to look at running headcount over time? For example, you work with employee level data which has Start Dates and End Dates and you'd like to be able to see how the total active headcount at the company has changed over the last 8 quarters.
That's something Tableau can do, but it isn't going to work out of the box. It's going to take some creative data structuring and calculations to get things working.