The purpose of this paper is to delineate the research challenges of human-machine collaboration in risky decision-making.Technological advances in machine intelligence have enabled a growing number of applications in human-machine collaborative decision-making.Therefore,it is desirable to achieve superior performance by fully leveraging human and machine capabilities.In risky decision-making,a human decision-maker is vulnerable to cognitive biases when judging the possible outcomes of a risky event,whereas a machine decision-maker cannot handle new and dynamic contexts with incomplete information well.We first summarize features of risky decision-making and possible biases of human decision-makers therein.Then,we argue the necessity and urgency of advancing human-machine collaboration in risky decision-making.Afterward,we review the literature on human-machine collaboration in a general decision context,from the perspectives of human-machine organization,relationship,and collaboration.Lastly,we propose challenges of enhancing human-machine communication and teamwork in risky decision-making,followed by future research avenues.