Since 1961, NIH has been offering Career Development Awards (CDA), K series, to support the development of outstanding researchers.  The K99/R00 Pathway to Independence Award specifically facilitates the transition from mentored research training to independent, tenure-track or equivalent faculty positions by providing funding during this transition to help the recipient launch competitive, independent research careers.  Funding from a K99 provides salary support, research development support, and indirect costs.  

NIH is made up of 27 Institutes and Centers, each with a specific research agenda.  Not all centers offer a CDA, so check for current funding opportunities regularly.  

From the NIH site: