Might be an agreement with AA with regard to the U.S. The CX Canada website used to market AAdvantage as its sole FFP up until 2 years ago when AAdvantage was dropped from any special mention.

The AA promotion dated back to early 2000 when CP was acquired by AC and the two airlines tried to stem defection to AC. CX granted a status match for anyone residing in Canada who had status on another carrier (namely, AC and CP elites who had received equivalent AC status). Also, anyone who resided in Canada and had flown a AA (or any OW) flight in the previous year was bumped up a status level and given 4 upgrades, and were granted much more liberal fare/mileage earning eligibility than anywhere else (for AA members at least) as well as reduced elite qualification to match AC (18k for GLD, 35k for PLT). Sadly, that all ended with the past 12 months.