According to the 9to5 Mac, apple users can turn noise cancellation on or off during calls through accessibility settings up to the iPhone 12 series. For an unknown reason, the feature was never available to iPhone 13 series users, who have been waiting for months in the hope that Apple will fix the problem.
Telephone noise cancellation refers to turning it on to reduce the ambient background noise in the phone when you hold the handset to your ear.
As shown in the picture above, on the left is the iPhone XS, which has this function, and on the right is the iPhone 13 Pro without the phone noise cancellation function. As of now, the only available workaround is to activate voice isolation in calls in the Control Center.
The problem was found to have come from a Reddit user posting that the iPhone 13 lacked a "front-facing microphone for noise cancellation." Later, an Apple community expert provided an article to help users adjust the audio settings on their iPhones.
You can adjust the left and right channel balance of mono audio and stereo to meet your listening needs. You can also turn on noise cancellation to reduce ambient background noise in your phone. The problem is that iPhone 13 users can't find this specific feature.
This discussion was almost two months ago. However, in Apple's recent release of iOS 15.2, this problem does not solve this problem, even in the iOS 15.3 beta, this problem still exists.