What's the difference between F5 refresh and Shift+F5 in Google Chrome browser?

It ignores the cached content when refreshing...

https://support.google.com/a/answer/3001912?hl=en

F5 or Control + R = Reload the current page
Control+Shift+R or Shift + F5 = Reload your current page, ignoring cached content

The difference is not just for Chrome but for most of the web browsers.

F5 refreshes the web page and often reloads the same page from the cached contents of the web browser. However, reloading from cache every time is not guaranteed and it also depends upon the cache expiry.

Shift + F5 forces the web browser to ignore its cached contents and retrieve a fresh copy of the web page into the browser.

Shift + F5 guarantees loading of latest contents of the web page.
However, depending upon the size of page, it is usually slower than F5.

You may want to refer to: What requests do browsers' "F5" and "Ctrl + F5" refreshes generate?

Reload the current page:
F5
or
CTRL + R


Reload the current page, ignoring cached content (i.e. JavaScript files, images, etc.):
SHIFT + F5
or
CTRL + F5
or
CTRL + SHIFT + R