Pros
A potential inroad into large client companies (Leave Cognizant ASAP)
You aren't unemployed.
Cons
It's a body shop.
Clients will view you accordingly. Contractors cannot be trusted with most tasks. You must be siloed (No room for growth) so you don't break anything. Your actual job is to fulfill gaps in the client's grunt work even if out of scope. If you don't, the hammer falls from client and Cognizant.
Wages well below industry standards. 1% annual raises only exist because legally they must exist. Takes full advantage of H-1B slave system, where employees' families and homes will be thrown into a furnace if you aren't keeping Cognizant happy no matter what.
Employees are complacent in their slavery. Management is just happy to get their extra crumbs and will reinforce the bad culture.
C-suite is opaque. If you are familiar with India's caste system you will understand how "lessers" are treated. This also happens in a literal sense, you aren't totally safe just because you are the favored skin tone.
Takes full advantage of modern white collar culture. "Your racist actions aren't actually racist if you aren't Caucasian." Expect the uphill battle to be even more steep if you're not Southeast Asian.
You will hunt for your own work most of the time. Cognizant is not helpful in any regard. They exist to skim off the top and nothing else.