The axion is a hypothetical pseudo-Goldstone boson proposed to dynamically resolve the strong CP problem, a long-standing mystery in quantum chromodynamics (QCD) of particle physics. In particular, the QCD axions with masses on the order of $\mu$eV to meV are a strong candidate for dark matter. The cavity haloscope is one of the most effective techniques to search for dark matter axions in the microwave region. A large cavity volume and low detector noise are crucial for high-frequency axion searches to improve experimental performance. Various novel cavity designs (based on multiple-cell design, wheel mechanism, and tunable photonic crystals) have been developed by IBS-CAPP for efficient searches for high-mass axions. Josephson parametric amplifiers developed by U. of Tokyo/RIKEN achieved near-quantum-limited performance. Utilizing these key components, CAPP is currently conducting leading haloscope experiments to explore the frequency range between 5 GHz and 25 GHz (20 $\mu$eV and 100 $\mu$eV) with KSVZ sensitivity. In this talk, we present the current status of these experiments and discuss future plans.