Therapeutic efficacy. a–c) After challenge with B16–F10 cells on day 0, mice were treated using CpG-CCNPs combined with a checkpoint blockade cocktail of anti-CTLA4 plus anti-PD1 (αCTLA4/αPD1), CpG-CCNPs alone, or the checkpoint blockade cocktail alone on days 1, 2, 4 and 7. Average tumor sizes (a), survival (b), and individual tumor growth kinetics (c) were plotted over time (n = 6; mean ± SEM). Reporting of average tumor sizes was halted after the first mouse died in each respective group. * p < 0.05, *** p < 0.001 (compared to CpG-CCNP + αCTLA4/αPD1 in survival plot); log-rank test.