The term Deepfake refers to artificially made media wherein the likeness of an individual in an existing video or image is replaced with someone else.
In essence, it is just a more high-tech and believable form of photoshopping.
Most Deepfakes are used for malicious or hilarious intents. However, some people behind these images and/or videos mean well. For example, the improved Deepfake version of the CGI'd Luke Skywalker that appeared in the season finale of The Mandalorian after it went viral.
Shamook lands a job over at Lucasfilm
Lucasfilm employed some Hollywood magic to make Mark Hamill appear as his younger and nimbler self during the closing episode of The Mandalorian season 2.