What needs to remain constant for boyle's law to hold true?

Boyle's law is a gas law which states that pressure and volume of a gas are inversely proportion to each other when temperature is kept constant.

Boyle's law states that at constant temperature for a fixed mass, the absolute pressure and the volume of a gas are inversely proportional. The law can also be stated in a slightly different manner, that the product of absolute pressure and volume is always constant.

I hope my answer has come to your help. God bless and have a nice day ahead!