I had the same question.
From what I have been able to learn online, there are a couple of approaches for code Income code: 46 (in my case Canadian CPP).
1. Convert the CAD box 16 into USD and add to Box 5 Net Benefits for 2022.
2. Check the box Railroad Retirement benefits (Form RRB-1099). Learn More refers to this as "How are taxable Social Security benefits calculated?" and answers the question "Are your Social Security or Railroad Retirement benefits taxable?" .
3. Convert the CAD box 16 into USD and add to the RRB-1099 Box 5 Net Social Security Equivalent Benefis Paid in 2022.
This has the same net effect as adding the US equivalent to box 16. The advantage I assume is I can see the different numbers reported in TurboTax. This whole approach is kinda "clunky" IMHO.
