No major conflicts, sure, but there’s been a handful of minor wars since WW2:
The Mexico-Guatemala conflict 1958-59
The Bay of Pigs invasion 1961
The Football War 1969 between Honduras and El Salvador
The invasion of Grenada 1983
The mining of Nicaraguan harbours by CIA in 1984*
The invasion of Panama 1989-1990
*there is some debate though whether this should be considered acts of war or of terrorism, considering that there was no declaration of war preceding the mining, which blew up several Nicaraguan fishing vessels and damaged several cargo ships from Europe and the Soviet Union. It has been compared to the German u-boats sinking vessels from neutral countries during WW1.
1950-53 the Korean war* There have been very few intercountry wars since World War II outside of the EU (though civil wars are frequently fought through foreign powers....)
1954-62 the Algerian war
1955-75 the Vietnam war
1956 the Suez crisis
1963-66 Indonesia-Malaysia confrontation
1965 Indo-Pakistani war of 1965
1967 the six day war
1967-1970 war of attrition
1968 Soviet invasion of Czechoslovakia
1969 Al Wadiah war (Saudia Arabia vs South Yemen)
1972 Tanzania invading Uganda
1973 Yom Kippur war
1974 Turkish invasion of Cyprus
1975 Indonesian invasion of East Timor
1975-89 Cambodian-Vietnamese war
1975-1991 Western Sahara war
1977 Libyan-Egyptian war
1977-78 Ethio-Somali war
1978-79 Uganda-Tanzanian war
1978-87 Chadian-Libyan
1979 Sino-Vietnamese war
1979-89 Soviet-Afghan war
1980-88 Iran-Iraq war
1981 Paquisha war (Peru vs Ecuador)
1982 the Falklands war
1982 Somali-Ethiopian border war
1983 Chadian-Nigerian war
1983 invasion of Grenada
1984-2003 Siachen conflict (India vs Pakistan)
1985 Agacher Strip war (Mali vs Burkina Faso)
1986 US bombing of Libya
1987 Sino-Indian conflict
1987-90 Kenya-Uganda border conflict
1988-94 First Nagorno-Karabakh war
1989-91 Mauretania-Senegal border war
1989-90 invasion of Panama
1990-91 Gulf war
1991-92 South Ossetia war (Russia vs Georgia)
1992-93 Abkhazia (Russia vs Georgia)
1995 Hanish Islands conflict (Eritrea vs Yemen)
1996-97 First Congo war
1998-99 South African intervention in Lesotho
1998-2000 Eritrean-Ethiopian War
1998-2003 Second Congo War
1999 Kargil war (India vs Pakistan)
2002-21 War in Afghanistan
2003-11 War in Iraq
2005 Bangladesh India border clash
2005-10 Chad-Sudan conflict
2008 Bangladesh India border clash
2008 Djiboutian-Eritrean border conflict
2008 Russo-Georgian war
2008-09 Gaza war
2008-12 Cambodian-Thai border dispute
2014 ongoing Russo-Ukrainian war
2016 Armenian-Azerbaijani clashes
2017 Afghan-Pakistani border skirmishes
2018 Armenian-Azerbaijani clashes
2019-20 Persian Gulf crisis
2020 Second Nagorno-Karabakh War
2020 China-India skirmishes
2020-21 Sudanese-Ethiopian clashes
2021 Kyrgyztan-Tajikistan conflict
2021 Armenia-Azerbaijan border
Just to mention a few...
... and then I’ve left out all the liberation wars in the wake of WW2, plus all civil wars including the conflicts in former Yugoslavia and the war in Syria as these could be considered civil wars, even though several recognised nations have had boots on the ground there.