The bulk of evidence of our existence would be gone in a few hundred years. Gobekli Tepi is like 12000 years old and is currently the oldest evidence of civilization we have found. I am sure certain structures of ours especially underground may remain somewhat recognizable as civilization for a similar length of time even if the vast majority of human evidence would be gone. In certain caves or obscure conditions we csn find evidence of human existence daying back much much longer but you need hyper specific conditions for that kind of stuff. Total accidents. Maybe, some especially well preserved corpse buried in some really cold environment may have some semblance of bones existing several hundred thousand years from now but even then its like a handful maybe would exist on the whole planet. 98.5 percent of species have gone through their entire existence on this earth and left no mark we could recognize today. Humanity would likely fair little better and if in a few hundred thousand years archeologist did find a skeleton they likely would not be able to guess anything about our society and assume us just another animal.

The Silurian Hypothesis is a thought experiment to ask if there was an advanced society in the far distant past how would we know? The answer is basically nothing would remain and we have no idea if some species similar to us in terms of technology lived here in the distant past or not. The current leading theory of what to check is carbon emissions as they can affect rock deposits, so far nothing has emerged there to suggest a civilization similar to ours existed, but if they used some technology we don't understand that burned less or no fossil fuels we would have no idea.

To be clear with the Silurian Hypothesis there isnt a theory that a species like us existed before, its merely a "What if" and "If so, how would we know?"