Before this new update, it was only possible to view Google Tasks entries via a dedicated app on mobile. But Google has started to roll out an update where the information you put in Tasks will show up in the Google Calendar app on both Android and iOS devices.
Like adding new calendar events, you can add tasks by tapping on the + sign to add new tasks. These will show up in the right sidebar or on the day they are scheduled. The rollout of the feature has started, and it will take a couple of weeks. So, be a bit patient if it hasn't made its way to you yet.
Source: Engadget