- Inclusion and exclusion criteria for this cohort are the same as above, with the following rule for CD4 count based on tolerability in Phase I; if, participants with lymphocyte T CD4 count between 100-200/mm^3 (Stratum 2) are shown to tolerate treatment in the Phase I dose de-escalation portion at the same dose level as those with CD4 counts > 200/mm^3 (Stratum 1), participants in the expansion cohort with CD4 counts >= 100/mm^3 are permitted; otherwise, the expansion is open to all solid tumor patients except those whose tumors are known not to respond to nivolumab (pancreas, prostate and MSS colon cancer); for the relapsed refractory HIV-cHL cohort, participants with CD4 count >= 100/mm^3 are permitted