First off, let me say that I'm a Wei-ist. I think Cao Cao is the hero of the age, and he is a good comparison with Julius Caesar historically and in the novel. So what do you think?
Expanded their territories immensely.
Noblemen with a knack for politics, but famous for their wars.
Both wrote books on warfare based on their experience. Caesar's Gallic Wars being read even until WW2 (a favorite of Chesty Puller's).
Both had a blood oath against them.
Both incredibly ambitious.
Both fought definitive battles against an old friend.
Both managed to have the political power close to an emperor while posing as something else (Caesar went the extra mile, but Cao Cao made opposition seem more helpless).
Both were succeeded by men who would become divine emperors.
Both changed the face of their nations forever.
Feel free to compare their merits and even go into VS a little too.
I think Caesar was a better conquerer, while Cao Cao was better at getting his enemies to play into his hands. Cao made good use of the northern tribes and the Gongsuns to finish off the Yuans, and if I am correct, he kept order by tightening the laws.