Cathay and Sorraine have no formal alliance, chiefly because Galiard never wanted an on-paper agreement with Caspius. They allied when Caspius declared for Cathay during the Kindaran war and there is considerable goodwill between the two realms, but there is also considerable skepticism, because Cathay was re-founded by everybody in Toupellon who wanted nothing to do with a Sartanist theocracy.
So it's a complicated relationship. Most individual nobles in Sorraine get along with most individual nobles in Cathay. But formal interactions between the Crown of Cathay and the Church of Sartan are dicey because Galiard doesn't even like having a Church addressing a King as any kind of equal in power.
