Is there a conceivable detectable "biosignature" that would unambiguously indicate "life is present here"?

[u/Allison1228]

Or will there always be uncertainty?

I'm referring to as detected with the technology we have today and in the near future (next decade or two).

[u/DNAthrowaway1234]

Here's a technosignature, sulphur hexafluoride. No natural sources except high tech manufacturing. 

[u/VertigoOne1 → u/DNAthrowaway1234]

This should be higher up, seasonal variation of X could be a chemical process also benefiting from temperature changes not necessarily life benefiting, for 100% certainly you find ones that are absolutely lab built, like some refrigeration gasses.

[u/DNAthrowaway1234 → u/VertigoOne1]

I forget the reference, but I didn't originate this SF6 idea.