In 2016, scientists announced that they might have spotted clouds in Pluto's atmosphere using New Horizons data. Investigators saw seven bright features that are near the terminator (the boundary between daylight and darkness), which is commonly where clouds form. The features are all low in altitude and roughly about the same size, indicating that these are separate features. The composition of these clouds, if they are indeed clouds, would likely be acetylene, ethane and hydrogen cyanide.
NASA's Hubble Space Telescope has also revealed evidence that Pluto's crust could contain complex organic molecules.