All Christians believe in Jesus. But just what that belief means and what its consequences are vary widely, so widely that Christians have gone to war against other Christians who believed differently.
Buddhism traces itself back about 2,600 years to Shakyamuni Buddha. But whether Buddha was a man or a divine being, someone to emulate or someone to pray to (or all or none of the above) is something Buddhists are far from unanimous about.
So the first thing Christianity and Buddhism have in common is that Christians disagree about Christianity and Buddhists disagree about Buddhism.
LJWorld.com / Faith Forum: What do Christianity and Buddhism have in common?