It is possible to send variables to templates using this exemple code:

{template="includeCSS" app="core" group="global" location="global" params="VARIABLES"}

Is it possible to send variables to a raw php Pages block?

{block="my_block_key" params="VARIABLES"}

 

No, but you may be able to set a session or global variable first if needed, or store data temporarily elsewhere.

{$_SESSION['tempvar']}
{block="blockkey"}