Well, the projection of Chris Lee's duet/co-performance in the Spring Festival Evening belongs to fantasy. In fact, holographic technology has been put into use for a long time. It just belongs to pseudoholography. Still need to use the media. Only the medium is very thin and transparent. It makes you feel nothing in the dim light, like appearing directly in the air. At present, all holograms on the market are like this.

Like pictures. There is a very thin holographic film. At present, this type of holography is mainly used for weddings, performances and so on. You can ask me for information if you like.