CAMEO will prepare CAMS for the uptake of upcoming satellite data, advance the data assimilation (DA) and inversion capacity of the global and regional CAMS production systems beyond the state-of-the-art and develop methods to provide novel uncertainty estimates for CAMS products in direct response to some of the main outstanding expressed user requirements. CAMEO will contribute to the medium- to long-term evolution of the CAMS production systems and products. The transfer of developments from CAMEO into subsequent improvements of CAMS operational service elements will be a main driver for the project.