#1楼 @small3flower 没写错,可以看看https://developer.apple.com/videos/play/wwdc2019/713/ ,这个 session 的第58分52秒开始:And Secure Transport, Does not support TLS 1.3, and it will never support TLS 1.3, another reason to use URLSession and Network.framework.
然后可以看看官方文档,https://developer.apple.com/documentation/security/secure_transport?language=objc#overview,Secure Transport 框架的确在 iOS 13/macOS 10.15 被废弃了,并且苹果推荐用 Network.framework 代替。