Still not seeing how Cerce became the next in line to the throne --> she's not a Baratheon, only by marriage. didn't think that put her in line of succession.
There are no trueborn Baratheon's left. Renly had no children and Stannis killed his before he died. The only persons left that have a stronger claim to the throne than the Lannister's are Jon, Dany, and Bran (and his claim is only slightly stronger than the Lannister's and everyone thinks he is dead anyway). The Targaryen blood line (which is how Robert took the throne) is all but eliminated except in ****s (such as Gendry - if he is even alive) and
Edited for profanity. Please do not do it again.s don't take the throne (without force).
Now technically since Jamie was no longer in the King's Guard, he would take the thrown before Cersei since he is the trueborn male heir (even though he is younger than Cersei), but that is a different sort of argument.
Of course none of that matters when you take the throne through force, which is exactly what Cersei did.