An ideal gas must strictly obey Boyle's and Charles' laws at all pressures and temperatures. An ideal gas does not exist.
Boyle's law
The pressure of a fixed mass of gas at constant temperature is inversely proportional to the volume.
Charles' law 1
The volume of a fixed mass of gas at constant pressure is proportional to the absolute temperature.
Note: zero Kelvin (absolute zero) is a temperature of about minus 273°C.
Charles' law 2
The pressure of a fixed mass of gas at constant volume is proportional to the absolute temperature.
Note: this law is the the working principle of the constant volume gas thermometer, which is of historical importance in the development of physics and the concept of temperature.
For all three relationships to be exactly true the molecules of an ideal gas must have no volume and there must be no forces between molecules. The molecules of a real gas occupy a small volume and there are weak attrative forces between molecules known a Van der Wal's forces. Real gasses approximate an ideal gas at low pressures.