Final answer:
Chimpanzees and humans diverged from a common ancestor about 6 million years ago, with the emergence of traits unique to humans evolving subsequently.
Step-by-step explanation:
Chimpanzees and humans are thought to have diverged from a common ancestor approximately 6 million years ago. This period is delineated by genetic studies and the fossil record, including the discovery of Sahelanthropus tchadensis, a fossil that lived around 7 million years ago and may represent the last common ancestor of humans and chimpanzees. Characteristics that distinguish humans from other hominoids, such as bipedality, increased brain size, and opposable thumbs, began to evolve after this divergence.