You can take a quiz to get 5 games in a tier 8 premium rental tank:
At the end you get a code to redeem based on your choices. You can take it unlimited times, but only redeem one code.
To save you some time, all the codes are in this format: IAM _ 2020 where _ is the name of the tank.
These tank (codes) are available:
M449 (AMX m4 49)
KJP105 (kanonen jpz)