.0000000000000003 atm or 0.3 nanopascals of atmosphere.
On Earth, this is considered to be a very good vacuum. In fact, the density of the atmosphere at the Moon's surface is comparable to the density of some of the outermost fringes of Earth's atmosphere, where the International Space Station orbits.
the Moon is considered not to have an atmosphere because it cannot absorb measurable quantities of radiation, does not appear layered or self-circulating, and requires constant replenishment due to the high rate at which its gases are lost into space.
I feel like saying the moon technically has an atmosphere is like saying an astronaut has an atmosphere if they farted in space sans spacesuit because some gas lingers around them.
Sometimes the always on healing works so good cells start doing things like reactivating telomerase and ignoring the signals for programmed cell death and become cancer, sometimes turning effectively immortal.