@ChristopherReed please push the deadline back to something like 2100 (as is standard for other questions like this); I think it's really unlikely for us to discover aliens by April 4th.
Requesting clarification: This is just about any aliens, not intelligent ones - so e.g. single-celled organisms on Mars would count?
Do they still have to be alive? If we find conclusive evidence that Mars had supported a specific single-celled species in its past, would that be sufficient for a Yes?
@ssh no, bacteria or other single celled organisms would not count. I'd say that the organisms have to be at least as smart as humans... We can probably count animals of different planets too(if they exist and have the physical features of Earth mammals)
@ChristopherReed I'd suggest changing "species" to "civilization" or similar in the title then (or at least be more specific in the market description)