Answer:
Cinna gives Katniss a few things such as the dress, the Mockingjay pin(previously given to Katniss in the Justice Building right after Katniss is taken to the Capitol), and a pair of gloves made for Gale.
Step-by-step explanation:
The pin is probably what you are talking about, so, I will use that. Cinna gives Katniss the pin because she forgot to take it with her. It reminds her of her home(District 12)