Do you have the idea of the pros and cons between GPU and CPU?

A CPU is good for general purpose computation. A GPU is kind of a specialized accelerator - for games, crypto mining, Folding@Home (protein dynamics), etc.

Need a proper balance between the GPU and CPU to prevent bottlenecks and get the best performance out of your system.

GPU is easier to upgrade, as CPU relies on the socket of the motherboard (which can change between generations) 

Basically, the CPU is important for everyday tasks and just making your computer feel quick. The GPU specializes in 3D graphics accelerate, but it can also be leverage for other specialized tasks especially when 3D displaying is unnecessary

CPU is the brain of a computer that runs all the processes and can handle multiple tasks very fast. GPU is a specialized microprocessor that enhances graphics and computing by using many smaller cores to process repetitive and highly-parallel tasks.

For most common PC programs/apps getting a computer with a Good/Newer CPU will get you a built in GPU that is good enough for most anything.  However if you intend to use games or programs like AutoCAD, that have a lot of graphics, you may need a separate dedicated GPU to handle the added video load.  But even a great stand alone GPU won't work well with an old or slow CPU; It can improve graphics, but a good CPU is still needed. 

Most CPU's, but not all, have integrated graphics built in and will do general purpose graphic workloads and even some very light gaming without GPU but any heavier graphics work and gaming will require a dedicated GPU.

They are made to process different types of instructions, you need  one or another depending on your work/usage needs

A CPU can handle any task, a GPU can complete certain specific tasks very quickly. CPUs can get bogged down when completing a lot of simple but time consuming tasks.

CPU affects most things on a PC, GPU is primarily for graphics processing like Photoshop, 3D Modeling, and Gaming.

From what I understand a dedicated or higher powered GPU is recommended for things like advanced Gaming and some application like machine learning/AI.
(Playing candy crush and similar casual games can be pretty much done on anything, Even cheap phones or tablets.So there would be no need to waste money on a dedicated GPU)
Other applications, like many graphics programs like Adobe, Photoshop.., even many video editing programs (unless they use GPU rendering). do better with a higher powered CPU, especially multi core CPUs.
It all depends on what you are going to be using it for. If you are going to need to use specific programs, getting some on information about their hardware requirements/recommendations would be helpful.