Triton is a moon of Neptune. It is made out of methane, nitrogen, and water ices, and rock. It could share a similar structure to Europa, with a subsurface ocean with volcanic vents. There could be strange forms of life on Triton.
However, life could be thriving now on Triton, but in 3.6 billion years, Triton will break up forming a new ring system around Neptune and this can impact whatever form of life that exists in the subsurface ocean of Triton.