Boston will send Kemba Walker, No. 16 overall picks in 2021, and the 2025 second-round pick to the Oklahoma City Thunder.
The Thunder will send Al Horford, Moses Brown, and a 2023 second-round pick to the Boston Celtics in exchange.
Walker is due to make over $73 million in the next two seasons with the 2022 player option worth over $37 million. OKC is likely to not be a winning situation in the 2021-2022 season so I would not be surprised if Kemba Walker is traded again.