In September 2021, Valve released an update that caused every map to be CT-sided. The update back then contained new features such as the upgrade and buff to the M4A1-s. Since that update, the graphs have shown that each map is a CT-sided map when looking at the round % distribution of wins between CT and T´s (Top 30 games). The switch in sides became such a big topic among all pro players that Valve quickly tried to even things out by nerfing the M4A1-s as well as making adjustments on different grenades.
You can read more about the graphs in the article below:
Post M4A1-s buff: Every competitive map are now CT-sided
A new update became active in early 2023 nerfing the M4A1-s. This has resulted in a more even game where the round % distribution of wins between CT and T´s is closer than ever before. Now, four out of seven maps in the active map pool are currently more T side than CT side.
% distribution of wins between CT and T’s (Top 30 games):
Ancient: 49,1% CT | 50,9% T
Anubis: 43,5% CT | 55,5% T
Inferno: 46,4% CT | 53,6 T
Mirage: 51,1% CT | 48,9% T
Nuke: 52,2% CT | 47,6% T
Overpass: 54,3% CT | 45,7% T
Vertigo: 48,5% CT | 51,5% T
