Path tracing
Full ray-tracing — simulates light bounces end-to-end.
Path tracing is the gold standard of computer-graphics rendering: rays are traced from the camera through every reflection, refraction, and bounce in the scene until they hit a light source or terminate. It's what offline render engines (Pixar, etc.) have used for decades; until Blackwell-class GPUs + DLSS 4, it was infeasible at interactive framerates. Cyberpunk 2077's Overdrive mode and Alan Wake 2 ship with path tracing as the headline RT mode.