From the description, you are suppose to use the I2C interface.
In order to use I2C interface correctly, you need connect CSB of BME280 to VDDIO and connect the SDO pin to either VDDIO (I2C address 0x 77) or GND (I2C address 0x 76).
Also you should put proper pull up register on the I2C line. i recommend you to use 4.3K first.
The issue for me looks like you don't put correct HW line connection.
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