It is confusing. Not only does Vietnam have two overwhelming and important cities of almost the same size, one of them seems to have two names that are both in use at the same time. Apart from Hanoi, the capital in the north of the country, there is also Ho Chi Minh City in the south. Or was it Saigon?
Well, the official name is Ho Chi Minh City (often abbreviated „HCMC“), although the southern metropolis has been called Saigon for centuries.
But after the Americans, and with them South Vietnam lost the war in 1975, North Vietnam took over and forcefully re-united the split country. Maybe the most in-your-face symbol of the victory was renaming the former capital of the South after the former leader of the North, Ho Chi Minh, in 1976. Since he had died six years earlier, this should not only make clear who was in charge now, but also make Ho Chi Minh immortal.
Do people care nowadays? Not really. Everybody will understand if you say Saigon. People are not irritated or aggrivated by foreigners using the old name, even most locals do. The Airport code is still SGN as well and let’s be honest: Saigon is a much better name than the not very catchy, rather long and complicated to spell „Ho Chi Minh City“.