3D films are motion pictures made to give an illusion of three-dimensional solidity, usually with the help of special glasses worn by viewers.
4K refers to screen resolution. HDR delivers a higher contrast—or larger color and brightness range—than Standard Dynamic Range (SDR), and is more visually impactful than 4K. That said, 4K delivers a sharper, more defined image.
Virtual production is where the physical and digital worlds meet. It lets directors work on a mocap stage, but view a virtual environment and characters. Virtual production has been around for years, but Avatar was the pivotal moment.