ΔE 18.4, loose: different enough that you should pick on purpose. Cobalt Bluegreen is noticeably lighter, cooler than Autumn Sage.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Cobalt Bluegreen is noticeably lighter, cooler than Autumn Sage.
The same difference applies the other way round: Autumn Sage is noticeably darker, warmer.
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 Autumn Sage on the colour wheel See Cobalt Bluegreen on the colour wheel
All matches: Autumn Sage equivalents · Cobalt Bluegreen equivalents