ILO NORMLEX Formerly ILOLEX, this site has information on International Labour Standards (such as ratification information, reporting requirements, comments of the ILO's supervisory bodies, etc.) as well as national labour and social security laws.
North American Agreement on Labor Cooperation: A Guide The NAALC was established under the NAFTA agreement between the U.S., Canada and Mexico. This is a link to a guide on the NAALC from the US Department of Labor.
Canada-United States-Mexico Agreement (CUSMA) - Chapter 23 - Labor - CUSMA (aka USMCA in the U.S. or T-MEC in Mexico) is the international trade agreement that replaced NAFTA. See also this summary on the chapter from Canadian government.