For this to resolve yes, there must be a broad consensus that the planet in question is a good candidate for hosting life because of the composition of its atmosphere. In other words, the atmospheric composition is not easily explained by geological or other non-biological processes, AND there is a compelling biological explanation.

Apr 16, 8:06pm: By 2035, will we have measure an exoplanet atmosphere whose composition is best explained by the presence of life? → By 2035, will we have measured an exoplanet atmosphere whose composition is best explained by the presence of life?