Displaying live XML data

I just started working at a company. They want me to do some maintenance work at there web-site, which is made with WordPress 4.0.

I do not have experience with WordPress. The simple things are not a problem. But they also want me to display live XML data.

I have done some searching, but until know I did not find something that would fit the bill.
Is there a plugin that could be used to display live XML data, or do I have to write my own plugin for this?

If I have to write my own plugin, I could use some pointers. I have a lot of programming experience, but am new to WordPress.