The Senate Intelligence Committee has declined Michael Flynn’s offer to testify in exchange for immunity. From CNBC:

The Senate Intelligence Committee has turned down Michael Flynn's request for immunity from prosecution in exchange for his testimony in the panel's probe into alleged Russian meddling in the 2016 election, congressional sources told NBC News.

Flynn's lawyer was told immunity was "wildly preliminary" and "not on the table" yet, a senior congressional official said, according to NBC.

Why would the Senate Intelligence Committee reject such an offer? Perhaps they already have the goods and don’t need to offer immunity in a criminal investigation.