This is the 3395th most frequent Turkish word.
kimliğine
"To your identity" or "to his/her identity."
"Kimliğine" here is used in the context of possession, indicating 'your ID'.
Kimliğine bakan görevli, bilgileri kontrol etti.
The official checking your ID verified the information.
"Kimliğine" indicates direct object with a possessive suffix, assigning the action toward 'your ID'.
Kimliğine zarar vermemeye dikkat et.
Be careful not to damage your ID.
"Kimliğine" is used metaphorically here to refer to suitability to your character or 'identity'.