Despite its age, Half-Life still has an active modding community and plenty of fans dedicated to creating interesting projects that enhance the overall experience of the game or its sequel.
Recently, a modder known as sultim_t released a launch trailer for their mod, which brings ray tracing to Half-Life. Similarly to how ray tracing was brought to Portal by Valve, sultim_t's mod updates the visuals of Half-Life brilliantly, giving us great new lighting effects, reflections, and more.
To handle this mod, you're going to need a graphics card capable of ray tracing, but beyond that, you should be good to go so long as you have Half-Life and download sultim_t's mod from the link provided in the description of the YouTube video below.
Are you going to be playing Half-Life with ray tracing? Check out the trailer here.