The LG smartphone calendar shows appointments and tasks from the app of the same name, but if you don't want to see them, you can hide them in the calendar.

Android 9 | LG UX 9.0
Events/Tasks -  Open the  Calendar -App
Events/Tasks -  Open the  Menu
Events/Tasks -  Open the  Settings
Events/Tasks -  Tap on  Calendar
Events/Tasks -  Enable or Disable  Show tasks
  1. Open the Calendar-App
  2. Open the Menu
  3. Open the Settings
  4. Tap on Calendar
  5. Enable or Disable Show tasks

LG Instructions