Honor is a call-out to the old Oriental Adventures book from AD&D days, while Sanity is a call-out to Call of Cthulhu (which had an official d20 adaptation during Third Edition).
Fifth Edition suggests you treat each as a separate stat, so if you use both, your characters will have eight stats. The rules also suggest situations where you'd have a player roll a characteristic check or saving throw based on each stat. (This means that, although the stats are inspired by other mechanics, they don't use the mechanics that inspired them, instead being much more integrated into the Fifth Edition core mechanics.)