Hi gkalyan,
The biggest difference between Markeo and Campaign is that Marketo's main focus is B2B marketing (account-based marketing, lead management, etc.), while Campaign is B2C. That said, for a comprehensive analysis as to what each one solves, you'll have to take a look at the specific product documentation, particularly for Campaign, as there are Campaign Standard and Campaign Classic, both of which have different capabilities.
Regards,
Craig
Craig