Cognizant — didn't get offer letter from 16th feb,2019 drive

Address: Khordha, Odisha

This is regarding the status of my offer letter from recruitment drive of cognizant held in bhubaneswar on february 16, 2019.

I have cleared the face to face interview of cognizant for technology teradata which was conducted on the above said date. I was also contacted from the recruitment team to fill the candidate information sheet multiple times, which i have completed.

I have again filled and submitted the candidate information sheet which was sent to me on 9th april, 2019.
I haven't received any further communication or offer letter.

I have appeared the cognizant drive for two consecutive years 2018 and 2019.
I cleared the interviews but never got the offer letter.
I don't understand if the company doesn't have openings why does it conduct recruitment drive every year.