The CBW Fentanyl Act amends existing law to allow the President to impose sanctions on foreign countries and individuals whose officials knowingly engage in chemical or biological weapons programs that cause harm to other nations. The bill specifically targets fentanyl precursors like benzylfentanyl and norfentanyl, establishing a framework where the President has 60 days to determine if someone has committed a covered act and must impose initial sanctions within 30 days, including suspension of scientific cooperation and restrictions on technology exports. The legislation creates a three-stage process with escalating penalties: initial sanctions automatically apply, intermediate sanctions can be imposed after 120 days if the foreign country hasn't adequately addressed the violation, and final sanctions can block all financial transactions after 210 days if issues remain unresolved. The President can remove sanctions after 12 months if the offending country has addressed the violation, developed prevention measures, shared information voluntarily, and complied with international chemical and biological weapons treaties. The bill includes a national security waiver provision allowing the President to delay sanctions for up to 180 days, but this waiver authority expires five years after the law's enactment.