Injecting carbon dioxide for shale gas recovery enhancement (CO2-ESGR) is an effective method to improve gas production and also realize the CO2 geosequestration. In the CO2-ESGR system, there are two-component gases (TCG) coexisted. The gas transport and adsorption mechanisms are different from the single-component gas system. However, most of current work is still focused on single-component gas (ie, methane). Many mechanisms have not been considered in the study of CO2-ESGR study. In order to conduct reliable numerical simulation for CO2-ESGR, a clear understanding of the transport and adsorption mechanisms for TCG system is necessary. In this review, we focused on two key issues regarding CO2-ESGR: the fluid transport and competitive adsorption. The fundamental mechanisms and models for pure gas and TCG transport have been comprehensively summarized. The adsorption models for TCG system have been reviewed and analyzed. Models such as extended Langmuir model, ideal adsorption solution model, and lattice density functional model have been compared. Also, the factors affecting the competitive adsorption of TCG in shale have been illustrated. The main factors include organic matter content, shale composition, pore structure, water content, and pressure. At last, the problems existed in current research of transport and adsorption models for TCG have been analyzed. The issues that are necessary to be considered in CO2-ESGR technology have been proposed so that more accurate numerical simulation and more reliable production prediction can be achieved.