The phrase "insidious ways" refers to deceptive or sneaky methods that are used to achieve something harmful or undesirable without being easily noticed or detected. Full definition
But odds are you'll be hacked in a more insidious way in 2016, sadder to say. (fortune.com)
Their holding back or internalising of emotions can be the most insidious way of coping for siblings. (fullcupplaytherapy.com)
He constructs cosmologies and interacts with the public in an environment removed from the setting of sponsored spaces where power and politics censor expression and control agendas in insidious ways. (artsatl.com)