GIFs support 8-bit pallets while PNGs support 24-bit or 32-bit.
Or in other terms, GIFs can support a maximum of 256 colors while PNGs can support over 16 million different colors.
So PNGs support more color than GIFs.
The image on the left is a PNG and the image on the right is a gif.
as you can see the image on the left has a much smoother variation of color than the one on the right.