Unfortunately vaccines are only 90-95% effective depending on the maker of the vaccine so you still can get COVID. The vaccine also only protects you and you can still pass COVID to other people even if you're vaccinated so masks are definitely here to stay.
https://www.hopkinsmedicine.org/health/conditions-and-diseases/coronavirus/covid-19-vaccine-what-you-need-to-know
https://www.health.harvard.edu/diseases-and-conditions/preventing-the-spread-of-the-coronavirus#:~:text=The answer is%2C we,protected from becoming sick.