Are We Looking for Life in the Atmosphere of Distant Planets?

With the advent of the James Webb Space Telescope, we are finally being able to detect molecules in the atmospheres of these distant planets. We're looking for muds, muds of fantastic and preserving signs of life but there are certain clay types that can only form through soil forming processes which linked to biology. So it's those clays we're after. And what about not Mars, but much farther away, Xander? You were saying that we can now see what's in the atmosphere of distant planets. Do we know what we're looking for, though? If we were to see a distant world, would we know what the signature in the atmosphere to look for that would tell us,