Recent progress in the molecular beam epitaxy (MBE) of CdHgTe/HgTe quantum well (QW) heterostructures paves the way to a new generation of photodetectors, light-emitting diodes and lasers [1,2]. A remarkable feature of such structures is the ability to suppress the Auger recombination in narrow (<10 nm) QWs in contrast to bulk-like wells [3]. In conjunction with a variable bandgap (from 0 to 1.5 eV), this feature allows developing long-wavelength lasers on interband transitions. Such lasers could be of use in 3.5-4.5 µm and 8-13.5 µm wavelength bands, corresponding to the atmospheric transparency windows, as well as in 25-50 µm range, where no quantum cascade lasers (QCLs) are available as yet. Coherent radiation from a HgCdTe (MCT) bulk alloy was first obtained in 1966 [4], 4 years after the very first semiconductor laser had appeared [5]. Interest in stimulated emission (SE) from MCT was revived in the 1990s [6,7], when the MCT growth technology was developing rapidly for the mid-infrared (IR) detectors [8]. However, this interest faded quickly, most likely due to the fast progress of mid-IR QCLs, happening about the same time. By 2015, the longest wavelength of coherent radiation obtained from MCT was 5.3 µm [6]. In recent years, some progress has been made as far as coherent radiation from MCT material is concerned [9][10][11]: in particular, SE up to ~20 µm has been demonstrated in [9]. The possibility of optical gain in HgCdTe QWs in 20-60 µm range has been already theoretically predicted [12]. However, for the development of lasers and photodetectors, scrutiny of carrier recombination is of paramount importance. CdHgTe/HgTe QW structures were poorly studied in this respect, especially as far as narrow-gap QWs are