Their cabins are almost always too warm nowadays. Just complain and they will make adjustments. Never used to be that way 5-10 years ago - they used to be nice and chilly like most other airlines but a few years ago the HK government came up with this silly idea of setting the air conditioning to 25.5 degrees celsius which is really not feasible in hot humid HK and definitely not in a cramped airline cabin - looks like CX followed the governments silly advice on this.

What they don't realize is that PAX that are cold can put on more layers or blankets, but PAX that are too warm can't exactly remove theirs!!