Forget the scientific name but I think this is called a Harlequin bug (at least that's what our family has always called them). Here in Australia, they are a tiny bit more blue. Was this one by any chance found on a hibiscus bush?
I should have put where this was found too: Canada, middle of nowhere on the western prairies. No hibiscus, and while we get some funky stink bugs and the like around, I don't tend to see them that colorful (to be fair, I rarely find nymphs either). Area low shrub line, sage and birch with wildflowers grasses and the like. I usually peak around there for Ambush Bugs and Annual Cicada when it gets well into summer, but that one was in around some Saskatoon bushes and tall grass.
Makes me wish I saw them more often to see what the adult forms (assuming it was a nymph) were, but the similar bugs are usually either greens or greys as adults, no idea if we have some cool predatory stink bugs though. I'll have to snag some more photos when I get back into the hills this summer.
@Ztesch There is absolutely no way that that is a reduviid. Reduviids (really, cimicomorphs in general) have elongated bodies with a more obvious abdomen-thorax distinction. Compare that to the squat figure and somewhat hard to see line between the abdomen and thorax on this pentatomorph. The white spots on the margins of the abdomen are pretty common on a variety of heteropterans. @Moebius Yeah, nymphs tend to be a lot more colorful than adults for stink bugs. There are a few exceptions where the adults look fantastic (Stiretrus anchorago, Perillus spp.), but that's the general rule, unfortunately.