In Counter-Strike 1.6, HLTV means literraly "Half-Life TV." This is a technology which allows the spectators to watch live broadcasts of Counter-Strike matches.
HLTV enables viewers to connect to a server as spectators and observe the ongoing game from the first person camera view.
HLTV servers usually host matches, and spectators can join these servers to watch the action live.
The system provides different camera angles and the ability to switch between players.
This technology was used in the development of esports, allowing fans to watch professional matches without interfering with the players gameplay.