Watching the fifth and last Indiana Jones movie, you can spot one of the latest developments in SFX, namely, the digital de-aging process. According to Wikipedia: "In motion pictures, whether for film (cinema), television, or streaming, de-aging is a visual effects technique used to make an actor or actress look younger, especially for flashback scenes. This is often accomplished via digitally editing the image or using computer-generated imagery (CGI) overlays or touch-ups."
In cartoons, the process is very easily achieved, as you can see here:
In real life pictures, the process is more complicated, but the results are similar:
However, the question remains: why can't they create something like this on real human beings?