From Longman Dictionary of Contemporary Englishdarkly funny/humorous/comicdarkly funny/humorous/comicdealing with something that is bad or upsetting in a funny way a darkly comic look at illness → darkly
Examples from the Corpus
darkly funny/humorous/comic• The show is a darkly comic look at medicine, money and morality.• Social Blunders, which follows the romantic misadventures of 33-year-old Sam Callahan, is a darkly comic romp through heartache. 