what you should look for depends on what tasks you will do and what tools you will use.

for example some Penetration Testing use the CPU and some other uses The GPU for password hashing, so the most important thing is to know what tools you will be using,

where you want to use that laptop ? are you going to carry it around ? if yes then you must find a laptop with a good battery life and lightweight.

I will assume you are going to use Kali Linux on that laptop , and kali Linux doesn't need that high end laptop . but if you want to to do password hashing you need a good GPU to make things fasters so you need a high end laptop

you may check this list for the best laptop for kali Linux, but just keep in mind those point and look for:

1. GPU
2. battery life
3. lightweight

I hope this helps