Game theory studies decision-making and strategic interactions among agents with competing interests, with applications from geosciences to credit risk. Beyond economics, late 2000s–2010s interest grew in applying game theory to optimization and big-data tasks (data fusion, feature selection, classification) for credit-risk modeling. Quantum game theory extends classical ideas using quantum mechanics, offering new insights into decision-making and optimization; research is accelerating and proponents call it groundbreaking for economics.