[maxerickson]

Pfizer worked with BioNTech, not Moderna.

Moderna's vaccine is a great deal easier to store than the BioNTech/Pfizer vaccine (requires 'normal' freezers for storage, can be at refrigerator temperatures for a longer period).

[denimnerd42]

BioNTech and Moderna both have links to Katalin Kariko so while they didn't explicitly work together on this the knowledge comes from similar research and sources.