Have to go back about another 100 years before the American Civil War for military useage of submarines.
Also, rifled bullets/artillery shells, breech loading rifles, cartriges and semi automatic (repeating) rifles first came in mass use during the American Civil War. Trench/defensive warfare was also adopted towards the end of the war for some of the major seiges (Petersburg for example).
There's other examples I could list, but I would say it's an understatement to say that the only direct use of 18th to 19th Century weaponary we still use to day is subs.
Trench warfare well pre-dates the US civil war. They were used at least as far back as the War of the Spanish Succession (1700s). The Maori also used trenches when fighting against the British, two decades before the US civil war.
Vauban [0] designed his first handbook for trench warfare after the Siege of Maastricht in 1673. Prior to that, siege mining and sapping had been used by Rome and Warring States China since about the 4th century BCE. This also marked the first purported use of poison gas in warfare, when the tunnels were intentionally filled with smoke.
