No sophonts? Or just us? ;)
The odds of their not being (now, then, before) any other sophonts are so long as to be not credible. Somewhere, somewhen, someplace in the many galaxies each with many stars, there is/was/will be (I am asserting but the math seems very likely) at least one other sophont society and quite likely many more. I saw an updated Drake Equation that posited with a conservative bent at least 10 other sophonts in the Milky Way alone. An optimistic view was around 200+. And that's in our one galaxy alone. There are many, many galaxies.
Now, will we ever meet any of them? That's a lot less likely. FTL seems impossible and may be so. Hypercomms might well be impossible too. So we might all, in our own corners of creation (like different bacteria strains in different petri dishes in a lab) end up evolving, growing higher order mental faculties, having our span, be it short or long on a galactic time scale (and humanity and even its distant progenitors are an eyeblink in cosmic time), and then falling.
If we don't get lucky and find another civilization that is a) in its period before it dies out, b) that is able to communicate with us in a way that is meaningful, and c) we possess the tools to communicate, we'll never even get to see or hear or communicate with any others.
In a way, I'm not sure that likely case isn't even more sad than 'no other sophonts exist'.
Cellular level life is even more certain to be encountered. That may be useful for us if we can ever leave this system, but if we cannot, then our span will be dictated by resource depletion, climate change, or the expiry of our star.
Still, that's a long way off, even in cosmic time.
TomB