I don’t have a Switch Online subscription, because I don’t play online multiplayer much. However, I know Hitman: WOA on Switch 2 is always online, even for single-player content, so do I need a subscription to play? Are there any features locked behind the subscription?
I can’t tell you about a subscription, but I can tell you if you bought HITMAN, you shouldn’t pay any more unless you want game upgrades or DLCs.
There is no hidden payments for the game, and as far as I know the game doesn’t provide anything that could be locked behind third-party subscriptions, i.e. some bonuses or exclusive content or whatever.
You just pay once and have the game as it is
You probably need the sub to play contracts and elusive targets, as these are stocked on IOI’s servers (and can’t be accessed while offline).