While it is theoretically possible for humans to come back after extinction, it is highly unlikely. This is because extinction usually occurs when a species loses the ability to reproduce or survive in its environment. If this happens, there is no way for the species to come back, even if conditions change in the future.
There have been a few cases where species have come back from near-extinction, such as the bison in North America. However, these cases are extremely rare, and they usually involve a combination of human intervention and favorable conditions.
In the case of humans, it is difficult to imagine what conditions could allow us to come back from extinction. We are a highly intelligent species with a complex culture, and we rely on a wide variety of resources to survive. If we were to become extinct, it would likely be due to a global catastrophe that would make it impossible for us to rebuild our civilization.
Despite the unlikelihood of humans ever returning, it is a fascinating thought to consider. If we were to come back, we might be a very different species than we are today. We might have new abilities and technologies, and we might be better adapted to the challenges of the future.