Pneumatic artificial muscles were inspired by human anatomy and apparently invented way back in the 1950s [1]. When I read about them in the late 1990s, they sounded interesting, but I don't think I've ever seen them in person. It seems like adding an air compressor to a robot is a big pain and most roboticists prefer to make do with electrical actuators instead. Groxx raises an excellent point in a sibling comment about unpredictable movement with soft actuators.

I just learned from that Wikipedia page that a version of the Shadow Dexterous Hand is actuated with pneumatic muscles [2].

[1] https://en.wikipedia.org/wiki/Pneumatic_artificial_muscles

[2] https://en.wikipedia.org/wiki/Shadow_Hand