I'm thinking of writing a story where due to magic, a bunch of Neolithic tribes get sent to the Late-Cretaceous Period.
While I was coming up with the idea, I realized that living with dinosaurs may cause a faster evolution in the advancement of armor and weapons.
While bone weapons were common for stone-age tribes, most Pleistocene animals didn't have claws or teeth as large as raptor claws could become. Large daggers made from therapod claws may become common within tribes. Spears could be made with horns of Ceratopsian dinosaurs, if possible to be wielded, hammers made from Ankylosaur/nodosaur clubs or Stegosaurian thagomizers as a club.
Another thing that may have evolved earlier is armor. Technically skins and hides could be considered armor, however, mammalian hides aren't really that good at protecting from clawing or bites and were more used to protect from weather.
However, many non-therapod dinosaurs had tougher scaly skin and scutes, so humans may take to wearing them as armor instead of just to protect them from the cold. Of course, it would be remiss not to point out that most predators would've probably been adapted to cut or bite through the rough scaly skin, so the armor probably would've been worn by those who got into conflicts with other humans.
Another thing is shields, humans will learn how to break off the frills of ceratopsian dinosaurs to use as shields.
This may also influence the design of shields later down the line. Bit of a time skip but I imagine once humanity enters the bronze age during these times, people in high status like commanders or generals, may have metal shields purposely designed and colored to look like that of a form of ceratops frill as a sign of status or power.