Since China has the most advanced network censorship, the Chinese have also invented the most advanced anti-censorship tools.
The first generation is shadowsocks. It basically encrypts the traffic from the beginning without any handshakes, so DPI cannot find out its nature. This is very simple and fast and should suffice in most places.
The second generation is the Trojan protocol. The lack of a handshake in shadowsocks is also a distinguishing feature that may alert the censor and the censor can decide to block shadowsocks traffic based on suspicions alone. Trojan instead tries to blend in the vast amount of HTTPS traffic over the Internet by pretending to be a normal Web server protected by HTTPS.
After Trojan, a plethora of protocol based on TLS camouflaging have been invented.
1. Add padding to avoid the TLS-in-TLS traffic characteristics in the original Trojan protocol. Protocols: XTLS-VLESS-VISION.
2. Use QUIC instead of TCP+TLS for better performance (very visible if your latency to your tunnel server is high). Protocols: Hysteria2 and TUIC.
3. Multiplex multiple proxy sessions in one TCP connection. Protocols: h2mux, smux, yamux.
4. Steal other websites' certificates. Protocols: ShadowTLS, ShadowQUIC, XTLS-REALITY.
Oh, and there is masking UDP traffic as ICMP traffic or TCP traffic to bypass ISP's QoS if you are proxying traffic through QUIC. Example: phantun.