Shrinkage and swelling in the matrix system of coal, lignite and shale beds are key phenomena during CO2 injection for enhanced methane recovery. Shrinkage improves permeability, while swelling reduces it, posing challenges for carbon capture, utilization and storage (CCUS), such as inefficient injection, reduced storage capacity and compromised reservoir integrity. Understanding these rock behaviours is critical to optimizing carbon storage and hydrocarbon recovery. Shrinkage and swelling are influenced by factors such as moisture content, pore distribution, mineral composition, organic maturity, temperature and pressure. In coalbed methane (CBM) and shale reservoirs, methane extraction reduces gas pressure, causing matrix shrinkage and enhancing gas flow. Conversely, CO2 injection leads to swelling due to its strong affinity for internal pore surfaces, reducing permeability and altering pore structure and fracture connectivity. To manage these effects, CO2 is often injected with N2 in tailored ratios. Laboratory-based sorption-induced strain measurements help determine optimal gas mixtures. A linear relationship exists between CO2 adsorption and strain greater adsorption leads to more swelling. Rock type, carbon content and thermal maturity also influence swelling behaviour, which is further affected by temperature and pressure. This review highlights key parameters of CO2 sorption and swelling, offering guidance to optimize gas production and reservoir performance.