IGBT is Darlington structure, MOS is not. Both IGBT and MOS require a certain threshold voltage (VGSth) to trigger the opening. However, due to the large parasitic capacitance caused by the Darlington structure of IGBT, certain gate driving capacity is required, while MOS is relatively small.
In contrast, the switching frequency of IGBT is generally low (below 30~50K) and the current is large (up to 1000A). The switching frequency of MOSFETs can reach 500K, while the RMS current is generally low (generally not more than 100A).