Both series involve 2 male leads who try and save a bankrupt/corrupt company,
The biggest difference would be that in Chief Kim, the male leads go from enemies to friends while in A2A, they remain friends all throughout. Chief Kim also has a more comedic tone while A2A is straight business and finance.
Both have a great story about business and finance, as well as a good bromance.
Both are about banking, and black sheep protagonists whose philosophy is that banking is about people rather than just money. Both show the drama of what is behind a loan, and how it ultimately impacts lives and the overall economy, although Hanzawa Naoki is far more suspenseful.
Both dramas show the business career development of young people, how creativity and prioritizing people in business is what creates real economic success. Much of the drama is also focused on the loyal friendships of the main characters. Whereas Akira to Akira doesn't have any comedic elements, and is specifically set in the banking world, if you enjoy it you'll likely enjoy HOPE, which has a similar progressive storyline.