Why Inbox app disturbs while notifications disabled? I get a notification each time when receiving an email although I disabled all notifications of Inbox. This fact is disturbing because Gmail app gives a notification too about the same event at the same time. 

Fig.  1 My settings of Inbox in Setting > Notifications > Apps 



Phone: Oneplus 2
System: CM 13
In your screenshot, the Block all setting is turned off. This means that notifications are not blocked from this app, so they'll appear as normal. If you want to disable notifications, change this setting to on, or turn off the notifications within the app itself.