Source: https://headphonesaddict.com/best-noise-isolating-earbuds/
There is quite a difference between noise isolation and noise cancellation that most people are probably not aware of.
Passive noise isolation isolates all outside sound, generally 25 dB – 30 dB, so if you want to lower all outside noise and just focus on your music, this is the best option.
Active noise canceling works slightly differently, it uses a microphone to record all low frequency noise, like the humming of a plane or helicopter engine (active noise canceling was first developed for helicopter pilots) and then sends the opposite sound to your ears through headphones to “cancel” it. This is a greatly simplified explanation. In the end, it usually cancels around 15 dB of noise.