COBOL (COmmon Business Oriented Language) was the product of a US Department of Defense initiative to develop a standard and portable programming language for business applications. COBOL celebrated its 50th birthday in 2009. It is generally believed that new COBOL development is in decline but a commercial commitment remains to keep the language relevant in today’s computing landscape.
The official COBOL standard is very slow to evolve due to a strong desire to keep the language relevant without compromising core strengths such as execution efficiency, interoperability with other languages and backward compatibility with earlier versions of the language.
The current COBOL ISO/IEC standard is ISO/IEC 1985:2014 Information technology -- Programming languages -- COBOL.
Vendors of course continue to issue new releases of their COBOL compilers with unique non-standard features from time to time. As a consequence, COBOL variants vary more than one might expect given the availability of standards.
There are several COBOL centered web sites where you can obtain further information:
Specific to Micro Focus COBOL Products:
Specific to IBM Enterprise COBOL for z/OS
Lightweight Editors with COBOL syntax highlighting
Various COBOL language code editor plugin are available:Source Info