Theoretical predictions suggest that cobalt-based nitrides could be unconventional high-temperature superconductors, but experimental evidence to support this is still lacking. Currently, the preparation of high-quality, compositionally precise, and reproducible CoN_x samples remains an unresolved challenge. In this work, we investigate cobalt nitride thin films, using radio-frequency nitrogen plasma-assisted pulsed laser deposition to initially fabricate high-quality epitaxial CoN_x films. X-ray diffraction reveals that the films exhibit a typical face-centered cubic crystal structure. Energy dispersive spectroscopy indicates that the nitrogen atomic percentage is close to 50%. Electrical transport measurements show that the samples exhibit metallic conductivity across the entire temperature range. Surprisingly, we observe a small but reproducible decrease in resistance with temperature across several independently fabricated samples. Magnetic field tests, both parallel and perpendicular, reveal clear signs of superconductivity suppression by the applied magnetic field. Furthermore, no significant ferromagnetic hysteresis is observed in the magnetization-field curve, ruling out the possibility of cobalt metal impurities in the sample. We are currently optimizing growth parameters and exploring ionic liquid regulation techniques to improve the purity of the superconducting phase. This research could provide a new platform for investigating the mechanism of unconventional high-temperature superconductivity.