If we know one thing about civilizations, it's that they leave shit around everywhere. If there once were a lot of folk about, there would still be shit for us to see today. We've looked, it seems pretty empty so far.

It would also be unlikely all of them would be dead, most sure, but not all. As far as we can see there is nothing.

We think there is almost certainly forms of life out there, stuff like single cell life. There's probably some of that in our solar system outside of Earth. More complex life would be way more rare, even multicellular would be rare. For a long time Earth was covered in sponges and it might have stopped there. And even if intelligence arises, they might not be tool users. Dolphins are pretty smart, they can't use fire or tools and won't be launching rockets any time soon. But let's say within the span of 100 million years about 10 human level civilizations would arise in our galaxy (which is probably a lot more than reality). What are the chances they get into space in a big way? Most of them would probably live in a gravity well deeper than us. That would make getting into space a lot harder. They might not have the energy budget, will or need to go into space. Their biology might be unsuited for it. But even if they do, getting to low orbit is one thing, getting beyond that is something we haven't even really done in a big way. Getting to other stars seems completely impossible with our current knowledge and no indication we are on a path to ever be able to do that. So say in the span of 100 million years there are two civilizations that live for 1 million years (we've only been around for a fraction of that). They would still most likely not only be thousands of light years apart, they would also be seperated by millions of years. And that's with some super optimistic assumptions.

So no, there is nobody out there.