Both are electromagnetic waves, quantized as photons. The only difference is the frequency of oscillation. Only wavelengths between 390 and 700 nm (approximately) are visible to humans. Radio waves are much longer (have much lower frequency).
source: https://www.quora.com/How-are-radio-waves-and-visible-light-different
Radio waves, gamma-rays, visible light, and all the other parts of the electromagnetic spectrum are electromagnetic radiation.