Currently watching the mini series, The Pacific, which made me realize the climate and terrain the Marines fought in during WW2 seem very similar to that of Vietnam. As well as the guerilla warfare and ambush tactics they encountered by the Japanese which the Vietcong also used.
Here's a near-identical question asked and answered, /u/GTFErinyes gives the best answer. https://www.reddit.com/r/AskHistorians/comments/6fz87v/for_the_us_the_vietnam_war_was_portrayed_as_an/