An ISO file is a "virtual" copy of an optical disc. For the original Xbox, these files contain the game's data, executable files ( default.xbe
To play an ISO on an original console, your Xbox must be (either via softmod or a hardmod/chip).
As we look to the future of gaming, it's clear that the legacy of the Xbox Classic will endure. Whether through official re-releases or community-driven efforts, the games of yesteryear will continue to entertain and inspire new generations of gamers.