The space agency's James Webb Space Telescope discovered a molecule called dimethyl sulphide, or DMS, on the distant planet, which on Earth can only be produced by life, according to a report from the BBC.
"On Earth, DMS is only produced by life. The bulk of it in Earth's atmosphere is emitted from phytoplankton in marine environments," University of Cambridge Profesor Nikku Madhusudhan, who led the research, told the BBC. More @ https://www.foxnews.com/us/nasa-detects-molecule-another-planet-only-produced-by-life
A spectrographic signature of a molecule is as unique as a fingerprint. They don't imitate one another. There is no answer to the question: What else can it be?
If I recall correctly, amino acids have been discovered in interstellar space as well. Does it prove the presence of life? No, it only proves that their formation does not depend on biology. And that may be all that this proves.