In this paper, we present HydraRPC, which utilizes CXL HDM for data transmission. By leveraging CXL, HydraRPC can benefit from memory sharing, memory semantics, and high scalability. As a result, expensive network rounds, memory copying, and serialization/deserialization are eliminated. Since CXL.cache protocols are not fully supported, we employ non-cachable sharing to bypass the CPU cache and design a busy-polling free notification mechanism. This ensures efficient data transmission without the need for constant polling. We conducted evaluations of HydraRPC on real CXL hardware, which showcased the potential efficiency of utilizing CXL HDM to build RPC systems.