Is cardio more important than weight training?
That depends on many things.
What are your goals?
By weight training do mean just lifting weights? Or do you include circuit training which is both weight lifting and cardio.
If you're only concerned with getting bigger, then compound lifts are more important (ie. squats, deadlifts, bench press, overhead press)
If you only want to be faster, sprinting will be more important.
If you want to be the best version of yourself, practically fit and healthy, then a combination of both are important.