Sometimes when we are writing articles with LaTex, thicker or thiner lines in the tables provide good and clear view on those tables. For instance, the one from the paper "aschern at SemEval-2020 Task 11: It Takes Three to Tango: RoBERTa, CRF, and Transfer Learning" at SemEval 2020 in the below, where the top and bottom lines are thicker than the middle line.
This can be simply achieved by using the makecell package and the corresponding command below:
First, just declaring we are using the makecell package
\usepackage{makecell}