What is the closest scientific branch to cognitive science? I was thinking about studying this awesome science but, unfortunately, it's not being taught anywhere in my country (Czechia). What is the closest scientific branch to cognitive sciences?
As @Lucianopaz said in his answer, this question is very broad and depends on what area of Cognitive Science you are interested in.

Cognitive Science is an "umbrella term" or a "collective term" for many different sciences.

As the link I provided says, there are 6 main sciences within the collection;


Philosophy
Linguistics
Anthropology
Neuroscience
AI (Artificial Intelligence)
Psychology


but within those sciences there are branches.

Take Psychology for example, and you could specialise in Social Psychology, Behavioural Psychology, Criminal Psychology... the list goes on.

You need to work out what interests you within this collection of sciences to work out what you want to study in college and university.