The piece of evidence that would most likely weaken the hypothesis that humans and chimpanzees share a more recent common ancestor compared to gorillas is:
Fossils of humans appear in deeper sedimentary rock layers compared to fossils of chimpanzees.
This suggests that humans and chimpanzees may not share a more recent common ancestor since it indicates that humans might be older or have a longer evolutionary history than chimpanzees, potentially contradicting the cladogram interpretation.