I think the scientists who discovered the phosphine are saying that there is
no known abiotic mechanism for producing the amounts they have seen.
They are asking the scientific community for ideas rather than shouting "LIFE!"
Still very interesting though.
I doubt that there's life on Venus, the conditions are extreme. The surface temperature is high, higher than that used for sterilizing equipment, and the atmosphere contains clouds of sulphuric acid, there's little or no water, atmospheric pressure is 50 bars and there's no magnetic field . The paper announcing the discovery is here . The interest in phospine as a marker for life on anoxic planets is discussed in this paper . So the interest is that if we can explain the presence of phosphine in Venus's atmosphere without recourse to anaerobic life then phospine is not a good biomarker for life on anoxic exoplanets. If, on the other hand, we actually do find extremophillic life there then there's a double discovery, that of life on Venus, and a proof-of-concept that detection of phosphine is indicative of the presence of life.