It works just like on your server or any MM game. There is no differences on FaceIT server. They might just run different server rates
Example:
//net_queued_packet_thread 1
//sv_parallel_packentities 0
//sv_parallel_sendsnapshot 0
sv_maxcmdrate 99
sv_minupdaterate 10
sv_maxupdaterate 100
sv_minrate 0
sv_maxrate 30000
Also they have custom PVS system (similar to SMAC anti wallhack addon) but it's way more better against cheaters. If the server won't send you information about enemy player = you don't have ab/tb/esp ez and simple as f***