PESTLE stands for political, economic, social, technological, legal, and environmental. It is a comprehensive way to scan the macro-environmental factors that influence your solution. You can use a PESTLE checklist to examine the trends, changes, and impacts of each factor on your solution. For example, a political factor could be a regulation or a policy, an economic factor could be a recession or a boom, a social factor could be a demographic or a cultural shift, a technological factor could be an innovation or a disruption, a legal factor could be a law or a contract, and an environmental factor could be a climate change or a natural disaster. A PESTLE analysis can help you understand the opportunities and threats in the external environment, the implications and constraints for your solution, and the alignment and compliance with the stakeholders' expectations.