People who work in companies that have government contracts like bridgebuilders etc. get drug tested regularly and cannot have Marijuana products on board. However never have seen hospitals or software companies or DC contracted companies have to pass that hurdle. And from monies and contracts flow freely there.
If you take CBD oil made from Hemp you should not test positive, if you take CBD oil from actual marijuana plants then you also should be okay except you chances are more likely to test positive, especially the product is not made by a reputable company.
https://www.medicalnewstoday.com/articles/hemp-cbd-vs-cannabis-cbd#hemp