I think that it might be a Tarnished Plant Bug but won't guarantee it with just one picture and no information. On what kinds of plants are you seeing these insects?

This is the only one that I've seen on one of my pole bean plants. I've been looking out for it but haven't seen it or any other of its kind since!

Beans are a known host plant, but I would not worry for one second about seeing a single individual. Now that you know what to look for, you can keep an eye out for them.

Thanks again!!