Does you laptop come with an MXM 3.0 Slot ? If NO, then you cannot upgrade the GPU, since the card might be soldered to the Motherboard..
Some more info on this issue, assuming you have one laptop that supports this feature.
MXM graphics cards are actually damn expensive as well. For the same price, you could get a desktop version of the card. A GTX 1060 card cost approximately USD400.
A GTX 1080 MXM graphics card costs about USD1000. That’s almost equivalent to the price of a gaming laptop. When you see prices like that you will quickly change your mind about getting an MXM graphics card.
Lastly, you need the hardware knowledge to properly install an MXM graphics card. If you are not careful you can easily destroy...