The Measuring Illicit Fentanyl Trafficking Act directs the Secretary of Homeland Security to develop performance metrics to track how effectively the department detects, deters, and seizes illicit fentanyl. The bill requires various components of the Department of Homeland Security to collaborate and share data with each other on fentanyl enforcement efforts, while also identifying any obstacles preventing information sharing. These performance metrics must align with the department's overall strategic goals for combating fentanyl trafficking. The Secretary has one year from the bill's enactment to establish these metrics and ensure coordination among relevant agencies. The legislation affects federal law enforcement agencies involved in border security and drug interdiction but does not include specific funding or authorization amounts.