What would imply that humans and fish had a common ancestor?

The presence of similar genetic sequences, particularly in key developmental genes, indicates a shared ancestry between humans and fish. Additionally, the existence of homologous structures, such as the skeletal framework of limbs and fins, supports the idea of common descent. Fossil records revealing transitional forms can also provide evidence of evolutionary links between these groups. Together, these factors suggest that humans and fish diverged from a common ancestor millions of years ago.