Infernape, one of the longtime kings of Gen 4 OU -while it is true that other Pokémon were far more dominant, few possessed as varied sets that adapted to such a rapidly evolving metagame, and hasn't dropped below UU in the generations that followed. Infernape's expansive movepool is thanks to that -Excellent STABs on both ends of the spectrum, coverage moves in Grass Knot, Stone Edge, U-Turn, Earthquake, Rock Slide, Poison Jab, support options in Fake Out, Endeavor, Taunt, Stealth Rock, Infernape can do anything except tanking (it does have Slack Off, but its Base Stats are a bit too high of a hurdle there).
The return to BDSP OU has been a mixed blessing for Infernape. On one hand, many of the faster Pokémon that were introduced are unavailable, enabling Infernape to wreak havoc as the pool of Pokémon that natively outspeed it is relatively small (Lati@s, Gengar, Alakazam, Dugtrio, Crobat, Azelf, Aerodactyl, Jolteon). On the other hand, Infernape hasn't changed that much, while its competition has. Clefable, once a wall that Infernape could nuke with its Fighting STAB is now a Fairy type that requires coverage or serious chip damage for Infernape to overcome. Azumarill is a veritable nightmare, being a lightweight Water Fairy type that requires Thunder Punch or Poison Jab to be seriously threatened and can OHKO with Aqua Jet. Other Pokémon that greatly benefit from their Hidden Abilities like Gliscor, Feraligator, Nidoking/Nidoqueen, Crawdaunt all give Infernape trouble or stop it before it can start. Additionally, the loss of Hidden Power means that Garchomp and Gliscor are solid answers to Infernape, though its Fighting/Fire STABs respectively will still sting.
Make no mistake, Infernape is on everyone's watch lists. It just can't carry every tool it wants and will always have fatal gaps in its coverage.
Mixed Monkey Melee
Infernape
Ability: Blaze
Item: Life Orb
-Fire Blast/Overheat
-Close Combat
-Grass Knot
-Stone Edge/U-Turn
Nature: Naive (+SPE, -SDEF)
EVs: 168 ATK / 88 SATK / 252 SPE
This Infernape set is meant as a potent revenge killer, breaking through popular defensive answers. Fire Blast + Close Combat eats the classic SkarmBliss Core alive, while hitting other potent threats like Scizor, Heatran (Attack EVs are to guarantee OHKO on Heatran), Magnezone, Tangrowth, Breloom, Weavile, Tyranitar, Bronzong, etc. Grass Knot is in general the best anti Water answer -crushing Gastrodon, Swampert, Quagsire, Blastoise, as well as Hippowdon. Last move is up to personal preference. Stone Edge punishes flying types like Dragonite, Salamence, Togekiss, and Gyarados, while U-Turn enables Infernape to scout and is the best option against Lati@s.
Other Options
Thunderpunch -Hits many of the lightweight Water types not bothered by Grass Knot as well as Gyarados and several Flying types
Poison Jab -Punishes Clefable, Azumarill, Ludicolo and Togekiss.
Slack Off -Recovers Damage from Entry Hazards and Life Orb, in case your opponent tries to wear Infernape down passively.