The threat landscape is the current mix of risks, threat actors, tools, and attack methods that defenders must account for. It is not a single threat, but the full operating environment: known malware families, emerging exploits, phishing tactics, insider risk, supply-chain abuse, and changes in attacker behavior.
This matters because security decisions depend on what is most likely to be used against you now. A changing threat landscape can make old controls less effective and shorten the time between a vulnerability being disclosed and being exploited. In practice, defenders track the threat landscape through threat intelligence, vulnerability management, logging, and detection engineering. If the landscape shifts toward faster exploitation, higher automation, or new abuse of AI, organizations need faster patching, tighter exposure management, and better monitoring to keep pace.