Frieza has so far helped the Universe 7. What exactly is Frieza's motivation in the Tournament of Power? Let's try to learn.
Frieza died as a tyrant, who did not regret one of his mistakes. This is evident after he was resurrected. He immediately tried to get revenge for his defeat at Namek.
Having been temporarily resurrected for the Tournament of Power, Frieza also shows he is still his old self. He greets Goku by punching the Saiyan man. Then he had time to trap Goku with Sidra's Devastating Energy. He even offered to help Universe 10.
From there it is clear that Frieza is not a trustworthy person. The immediate audience believes he will betray Universe 7.
He once worked with Frost and attacked Gohan. But it was revealed then that he only did that so he could get rid of Frost quickly and easily. When Goku asks for energy for Spirit Bomb, Frieza hands it over with pleasure.
The climax of the events in Dragon Ball Super 111 yesterday. Goku may not be able to fight anymore, considering he was badly wounded, exhausted, and can not eat Senzu nuts. Then Frieza appears, apparently to kill him.
In fact, Frieza actually heals Goku. He says that he does not want to fight Jiren, so he asks Goku to find a way to fight the strongest fighters in the tournament.
It seems impossible Frieza just kind. But what exactly is Frieza's motivation, which suddenly decides to be good after previously trying to move to Universe 10?
To read Frieza's motivation, remember first what a prize for the tournament winners: their wish will be granted by the Super Dragon Ball.
The Super Dragon Ball was last shown to grant only one request. So in the end, there should only be one request realized by Super Shenron. (Unless Zen-Oh decides to tamper with Super Shenron's ability).
The potential offered by Super Dragon Ball goes beyond all other Dragon Ball variations. Frieza is shown to hate Beerus and is glad to see the gods in shock. So it seems he has saved a very evil plan.
Continued discussion of Frieza's motivation can you read on the second page