ideal gas is basically a hypothetical situation. we just assume that 1) there are no intermolecular forces between the gas molecules and 2) occupy a negligable volume compared to the container. this is done so that PV=nRT can be used to calculate stuff.
real gases are exactly that... real lol. that formula is not valid anymore, but if we just tweek it a bit to take into considerations those two assumptions, we are good to go.
Hope that helped!