I'm trying to create a macro that can cast renew (on myself or mouseover - if even possible on some player that has no renew tinking on em ) and when renew is on CD to cast jab/expel harm .
#showtooltip [mouseover,help,exists] Renewing Mist; Jab -not working for me (doing nothing)
You can't have a macro take cooldowns into account for what it casts, or whether you have a certain buff/debuff or not (Renewing Mist in this case). There's about 10,000 websites/forum posts out there that tell you this. Try this.
Also, the macro you wrote has no /cast command, so of course it's not going to do anything.
For Renewing Mist, you might want to add a condition in case you have no mouseover target. You don't need to have both [help] and [exists] because [help] automatically includes [exists].
Because macros can't take cooldowns into account, you could use a /castsequence macro. Basically, you would add in a number of spells that when cast and taking the global cooldown into account, eventually cast the cooldown spell again when it (hopefully/probably) has come off cooldown. However, this is not guaranteed, and they are generally not a good idea for optimizing your performance.