While the exact species is unknown, it's important to understand that the cheetah is actually more closely related to the cougar and the jaguarundi than to the leopard, despite its superficial resemblance to other big cats. This is because the cheetah belongs to a distinct genus, _Acinonyx_, which diverged from the _Panthera_ lineage much earlier.
Therefore, tracing back to the common ancestor of the leopard and cheetah requires tracing back to the early evolutionary history of the genus _Panthera_, which is still being studied and debated by scientists.