Scrum Framework - All the events feed the Product Backlog
In the Scrum framework figure, it looks as if only the Sprint Review provides feed to the Product Backlog, in fact for all the events where the empirical Scrum three pillars Transparency, Inspection and Adaptation applied, eventually leads to possibilities for the Product Backlog refinement/addition as well. So the Scrum Framework figure also to be imagined accordingly.
PB is touched during sprint planning in order for the Developers to select PBIs for the SB.
Daily scrum is for the Developers so this usually means that PBIs in the SB are discussed and not the ones still in the PB; however, one cannot rule out the fact that there might be a situation that arises where this would be the case.
Sprint review will include the PB in order to discuss it with the stakeholders and scrum team.
Sprint retrospective could cause PBIs to be created in PB that relate to scrum team improvements.
Also remember that PB refinement occurs throughout the sprint.