Buff overgrowth for junglers.
Basically when you take a camp, gromp for example, it appears as +4 in your cs counter but overgrowth counts it as a single monster. That's why stacking overgrowth is pain in the ass for junglers.
It should count as 4 monsters for buffs, gromp etc...
It shouldn't be a big deal tbh but there aren't many defensive options in the jungle rn. Outside of conditioning and bone plating (which are on the same row) the other runes are lackluster.