Programmers have long been obsessed with fonts, and monospace font types (a long time Consolas user myself) have been their favorite. In programming a lot of character sequences are used to denote a particular operation, for example ->, <= , ==, === , !== and so on. The programmers mind has tuned itself to read these sequence of characters as a single logical unit of operation. Wouldn't it be nice to have them denoted as the way we do it in mathematics, more succinctly. Here is a comparison of few well known operators on how they rendered in your editor with and without ligature symbols.
Free monospaced fonts with ligatures:

• Fira Code
• Monoid
• Hasklig
• Fixedsys Excelsior
• Iosevka
• DejaVu Sans Code

Using Fira Code with VSCode:

Once you installed the font. Open settings.json

Mac: cmd+,
Windows / Linux: File -> Preferences -> Settings

add the following:

"editor.fontFamily": "Fira Code Retina",
"editor.fontSize": 14,
"editor.fontLigatures": true