The recent progress in the theoretical/numerical studies of cavity solitons in semiconductor microresonators, following the development of more refined models to adequately describe the complex physics of broad-area semiconductor microresonators, is presented. In particular, a microscopic model is discussed to describe the nonlinear response of a multiple quantum well sample, including the most relevant many-body effects in the framework of the Pade approximation. Both the passive and the active configurations are considered. In the latter case, a population inversion in the medium is sustained by means of carrier injection, in such a way that the device is maintained below the lasing threshold.