Hi grossi6330 and welcome to the forum.
AT5 will almost certainly run on a 2015 Mac Pro. However, to be sure, you should download and install the AmpliTube 5CS version that is available in your User Area on the main site.
This is a free, cut down version of the full software so you can confirm it will run on your system, as well as checking out some of the features and gear of the full version. You'll need to authorise it using the serial number you will also see in your User Area, to move it out of Demo mode.
grossi6330 wrote:I'm very interested inpurchasing the IK interface
Are you talking about one of the audio interfaces that IKM offer? If so, again, they should run on your system, but you should check the relevant details on the product page to confirm that.
Hope that helps.