It's been done but it's not for the inexperienced, and on some laptops it's not possible to upgrade either of those.
Maybe the CPU can be ugraded but you'd need to know which model processors are compatible, and that kind of info is difficult to find for laptops.
As for upgrading the graphics chip, that component is almost always non-upgradable since it's usually soldered directly to the main board.
I know of cases where someone has tried to upgrade those components on their laptop and managed to damage other components in the process. Ended up having to fit a new motherboard.
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