Welcome to AndroidCentral and thanks for the question.
The Google Pixel screen is protected by "2.5D Corning Gorilla Glass 4" which means it's pretty strong. A lot of customers get a screen protector just for that little bit of extra protection but if you take care of your Pixel, then there should be no worries about it getting broken or cracked.
I just cracked my screen a couple days ago. It fell about 8" onto concern,now I have e a nice long crack. Luckily it's not super noticeable unless the screen is off.