Check out example codes for "refusing to merge unrelated histories". It will help you in understanding the concepts better.

Code Example 1

git pull origin master --allow-unrelated-histories

Code Example 2

git pull --allow-unrelated-histories origin master

Code Example 3

git pull origin master --allow-unrelated-histories
#IF THAT DOESN'T WORK, REPLACE 'origin master' WITH THE REPO YOU WANT TO PULL FROM

Code Example 4

git pull origin branchname --allow-unrelated-histories

Code Example 5

git pull origin master --allow-unrelated-histories

Code Example 6

git pull origin master --allow-unrelated-histories

Learn ReactJs, React Native from akashmittal.com