Aubameyang is a kind of player who will do well in any league he goes to, we have seen in past years how well he did playing in Germany, England and Spain and now coming back to England feels like coming back to continue from where he left off just playing in a different jersey. He has the ability to succeed in tough leagues, it will be almost as the same as when he played for the Gunners.
I second that, tbh i don't see any reason why anyone would doubt what Aubameyang is capable of doing in Chelsea, i mean, it is not like he has flopped in any of his previois teams, it is either he wanted to leave, or he had problems with the manager like at Arsenal, or he simply fell out of favor because the club signed a better striker than him, like at Barcelona. Thus Aubameyang will have no problems succeeding at Stamford Bridge, and under the management of his former coach whom he so much did well under, in the past.
Having said that, Chelsea need a striker and now they have one, it is now time for Tuchel to decide which is his best formation, and pick the team he considers the strongest, Sterling can now play far out wide with Aubameyang in the center, it is going to be interesting and i am pretty sure Chelsea fans will be looking forward to what is to come for their club.