Cold War: Approximately 1947 (due to U.S. President Harry Truman’s Truman Doctrine) to 1991 (Operation Desert Storm, collapse of Soviet Union).
NATO reporting name Hip. The Михаил Мил Ми-8 (Mikhail Mil Mi-8) rotary wing began military service in 1968, with the Soviet Union. First production was done in the Kazakh Soviet Socialist Republic. The Mi-17 Hip has more powerful turbines than the Mi-8 Hip, also, the position of the tail rotor is different.
The Mi-8 is also used by silly-vilian (civilian) transport companies. I have several Western/NATO publications from the 1970s that speculate that the Mi-8 started military service prior to 1967. The earliest photos I’ve found of the Hip are from the early 1970s.

Soviet Hip visiting Little Diomede, Alaska, part of Operation Bering Bridge to help Alaskan Eskimos visit their relatives in the Soviet Union. Photo by Master Sergeant Ed Boyce, 23APR1989.
Post Cold War, Balkan Wars, War on Terror, Battle for Ukraine, 1992 to present:

Kazak Hip during the international Central Asian ‘Peacekeeping’ Battalion 2000 so-called humanitarian wargame in Kazakhstan. U.S. Air Force photo by Technical Sergeant Jim Varhegyi, 10SEP2000.
In 2005, a new Hip was created with improved turbines, larger cargo door, it was called the Mi-8AMT, but the export version is known as the Mi-171.

United Nations’ Hip during Operation Jingle Air in Afghanistan, 07JUN2008. U.S. Army photo by Sergeant Charles Brice.
U.S. Air Force video (by Technical Sergeant Scott Wilcox), Afghans prep their new U.S. taxpayer funded Hip for take-off, 10NOV2009:
Vehicle I-D, 2009-2018:

Russian Hips in Arkalyk, Kazakhstan, moments before taking off to support the landing of another Soyuz spacecraft, 08MAR2010. Photo credit Bill Ingalls.
Vehicle I-D, 2010-2017:
MARINA ARMADA DE MÉXICO MIL 17
Croat Mi-171 Hip, 29MAY2012, U.S. Army video by Staff Sergeant Jose Ibarra:

Czech Republic (Czechia) Hips on the Baumholder Training Support Center, Germany, for a NATO wargame, 12SEP2014. U.S. Army photo by Ruediger Hess.
Мил Ми-8MTV5 (Mil Mi-8MTV5, export version Mi-17V5) during Russia’s Vostock wargame in the Eastern Military District, 11-17SEP2018:

U.S. Army photo by Sergeant James Lefty Larimer. A ‘hip’ Egyptian helicopter (Mil 17V-5) conducting med-evac (medical evacuation) training during Bright Star 2018.
(See more Egyptian helicopters.)
Sling Load 2019: CH-47 CHINOOK COLLECTS MIL 8 ‘HIP’ BONES
Government Shenanigans 2020: UH-60 FOR AFGHANISTAN, KILLED-OFF BY THE MIL 17, U.S. TAXPAYERS RAPED TWICE?
NATO wargame Rapid Trident 2021: UKRAINE’s MIL 8MT/MSB-V
June 2022: Ukraine now using the Hips they were supposed to repair for Afghanistan
January 2023: Nigér loses Mi-17Sh helicopter during training
February 2023: Iraq gives up it fleet of Hips due to lack of spare parts

NATO-Poland Hip gives British Royal Lancers a lift, as part of NATO’s Task Force Ivy training. U.S. Army photo by Sergeant Alex Soliday, 19JUL2023.
July 2023: The Kyrgyz Air Force Receives A New MI-17V-5 Helicopter From Russia
August 2023: Russian pilot defects to Ukraine with an Mi-8 assault helicopter
NATO-Poland to replace its Hip helicopters
Cold War & Beyond: MIL 26 HALO, COLD WAR HELICOPTER WITH NO PLANS TO RETIRE!
Vehicle I-D: T-34-85, FROM PATRIOTIC WAR TO COLD WAR AND BEYOND?