The comedic timing and awkward moments are very similar. Reply 1988 has the goat noises, while Prison Playbook has a soft whistle track playing whenever there's an awkward moment; you could interchange those 2 sounds and get a similar feeling.
Also some of the characters are very similar such as Taek and Je-Hyeok. Both are like prodigies and very popular (Baduk and baseball) but they aren't ignorant of the ways of the world and rely on others to pull them along.

Both portray a mix of character stories (the writers really gave these characters depth) with very similar comedic timing. They deal with some serious themes but also have a bit of the quirky/awkward moments and making them gold. These are the kinds of shows where I'd like to say "Don't judge a book by its cover".

Both involve a revenge plot based on an injustice in their youth (involving their fathers) and a slow but steady process to reach their goals. Food and business competition. Corruption: those with money are above the law, while the poor end up receiving the punishments of those in power.