Some difference between HTML and XML are...

1.HTML was designed to display data with focus on how data looks while XML was designed to be a software and hardware independent tool used to transport and store data, with focus on what data is.

2.HTML is a markup language itself while XML provides a framework for defining markup languages.

3.HTML is a presentation language while XML is neither a programming language nor a presentation language.

4.HTML is case insensitive while XML is case sensitive.

5.HTML is used for designing a web-page to be rendered on the client side while XML is used basically to transport data between the application and the database.