Compared with the infrared photon detectors fabricated from other materials, the infrared detectors fabricated from mercury cadmium telluride (MCT) have several advantages of highly tunable bandgap, high quantum efficiency and R0A approaching the theoretical limit. The main drawback of the MCT detectors is that they have need to use cryogenic cooling to suppress the thermal-induced free carriers resulting in noise. It is desirable that the MCT detectors can operate at high operating temperatures (HOT) without sacrificing their performance. The HOT/MCT detectors are designed mainly to suppress Auger processes so as to reduce noise and degrade cryogenic cooling requirement. Starting from related basic concepts, the understanding of the physical mechanism of HOT/MCT is discussed and the development of the HOT/MCT detection technology in recent years is presented.