With increasing availability of spectrum in the market due to new spectrum allocation and re-farming bands from previous cellular generation networks, a more flexible, efficient, and green use of the spectrum becomes an important topic in 5G-Advanced. In this article, we provide an over-view of the 3rd Generation Partnership Project (3GPP) work on flexible spectrum orchestration for carrier aggregation (CA). The configuration settings, requirements, and potential specification impacts are analyzed. A few Release 18 techniques, such as multi-cell scheduling, transmitter switching, and network energy saving, are also presented. Evaluation results show that clear performance gain can be achieved by these techniques.