Because of the current trend for many Moslem nations to officially recognize or increase military and economic cooperation with Israel, the U.S. has reclassified Israel as part of CENTCOM (CENTRAL Command) rather than EUCOM (European Command) which includes nations in Europe, including Russia CENTCOM covers the Middle East, Southwest Asia, northwest Africa and the Persian Gulf. Israel was part of EUCOM from the beginning (1948) while CENTCOM was created in the 1980s because of where it was. Because of that Israel, which has always been more involved with nations in CENTCOM rather than EUCOM. Israel has always been the most powerful and cooperative ally of the United States in CENTCOM and has become the most advanced military, economic and scientific nation in the region. During that time Israel was, for all practical matters, part of CENTCOM and regularly traded, trained, and shared intel with CENTCOM and nations in CENTCOM as well as NATO nations in EUCON. Most EUCOM nations had diplomatic and trading relationships with the Moslem nations in CENTCOM. Since the 1990s the major military threat to Europe in CENTCOM was Iran and in the last decade Iran has declared most Arab nations in the regions as enemies and become a military threat to all of them, along with Israel and the United States. This put Israel in a unique position as it has long seen EUCOM nations as allies and was treated as a peer by European countries. Moslem nations long agreed with that but now see that as an advantage, not a threat. The result is Israel officially becoming part of CENTCOM. This has made it easier for Israel and the United States to coordinate military operations, including joint naval patrols in the Eastern Mediterranean and Red Sea. It is easier to plan joint operations against Iran and any other threats in CENTCOM.
Currently the United States military has seven unified geographic combatant commands in which a four-star general or admiral controls all American military units in a geographic area. The origins of the geographic commands began with the two global military commands the U.S. created during World War II to provide a unified command for all American forces in the Pacific and Europe. After the war, these two commands became regional unified combatant commands known as EUCOM (for Europe, including the Soviet Union) and PACCOM for the Pacific region, including Korea and China. In 1963 SOUTHCOM was created for Latin America. In 1983 CENTCOM (Central Command) was created for the Middle East and was followed in 2002 by NORTHCOM for North America. In 2007 AFRICOM was created for African nations not already part of CENTCOM. In 2019 SPACECOM was added to handle orbital forces and the earth-based units that put satellites and other structures into orbit.
For decades the four star-generals or admirals in charge of the regional commands were called CINCs (for Commander in Chief.) In 2002 that was changed because the president of the United States, who is, per the constitution, the "commander in chief of the armed forces" would be the only one referred to as CINC. The old CINCs would be referred to by new titles, like Commander, US Central Command. Despite that the commanders of the regional commands continued to be known, unofficially, as CINCs. Over the years that term was used less and less as a new generation got used to using the term “commander” for the senior officers running the regional commands.