Alexander Volkanovski is the current UFC Featherweight (145lb) Champion.
Yair Rodriguez is the interim UFC Featherweight Champion. The interim championship was created for the featherweight division as Volkanovski was temporarily busy with a fight at Lightweight (155lbs) and therefore wasn't around to defend the Featherweight title.
That fight has now been done, and Yair winning the interim title means he is now the natural next contender in line to fight for the FW title against Volkanovski, and this will presumably the next fight for both of them.
If Volkanovski wins this fight, this market will resolve to YES.
If Yair wins, or the fight results in a draw, this market will resolve to NO.
If it is called a No Contest on the night, or this is not the next fight for either of them, this market will resolve to N/A.