This paper presents the results of optical studies of a long-wavelength HgTe/CdHgTe heterostructure performed using photoluminescence and photoreflectance methods. Optical transitions involving several electron and hole levels were observed, with the dominant levels switching with changes in temperature. Using the photoreflectance method, optical transitions not detectable by the photoluminescence were observed. It is demonstrated that the combination of the methods allows for the most detailed evaluation of optical transitions in the HgTe/CdHgTe quantum wells.