In this paper, we present latest advancements in Ambient IoT (A-IoT) research within 3GPP and explore the challenges of introducing Ambient IoT technology into 3GPP system. We also propose key design directions for both current and future 3GPP releases. The diverse use cases, device types, design targets, and topologies of A-IoT poses significant design challenges due to the factors such as energy harvesting, need for low cost, power, and complexity. Additionally, mechanisms differ from existing 3GPP technologies. We introduce feasible high level design directions, including waveform, modulation, multiplexing, duty-cycled monitoring, random access, continuous wave (CW) interference cancellation, and proximity determination.