Black and orange fly
This is a sawfly adult (https://www.canr.msu.edu/resources/sawflies). The larvae are herbivores, though control depends on the amount of sawflies on your plants. If you know which plant where this insect was found, this would help me identify the insect to a lower taxonomic level.
It is on my hollyhocks.
This insect is definitely not a beneficial insect. From the photo, it might be a hibiscus sawfly (https://content.ces.ncsu.edu/hibiscus-sawfly#:~:text=Hibiscus%20sawfly%20adults%20are%20small,four%20antennae%20instead%20of%20two!&text=From%20that%20emerges%20a%20new%20adult%20to%20mate%20and%20lay%20eggs.)
There is a hollyhock sawfly (https://bugguide.net/node/view/208099). It does appear vaguely similar, though I am not aware of any records of this insect in MI.