ΔE 6.3, close: similar, with a visible difference side by side. Warm Skin Tone is more saturated than Graveyard Earth. They are different kinds of paint: AMMO by Mig Graveyard Earth is an opaque base/layer paint and Army Painter Warm Skin Tone is a wash/shade, so they won’t behave the same on the model even where the colour is close.
Usually, if you are not matching paint already on the model. Close match (ΔE 6). Warm Skin Tone is more saturated than Graveyard Earth. They are different kinds of paint.
The same difference applies the other way round: Graveyard Earth is more muted.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Graveyard Earth on the colour wheel See Warm Skin Tone on the colour wheel
All matches: Graveyard Earth equivalents · Warm Skin Tone equivalents