This paper reviews options for CMOS scaling for the 22nm node and beyond. Advanced transistor architectures such as ultra-thin body (UTB), FinFET, gate-all-around (GAA) and vertical options are discussed. Technology challenges faced by all architectures (such as variation, resistance, and capacitance) are analyzed in relation to recent research results. The impact on the CMOS scaling roadmap of system-on-chip (SOC) technologies is reviewed.